mmc: initialize struct mmc_data at declaration time

Converts from:
	struct mmc_data data;
	memset(&data, 0, sizeof(struct mmc_data));

to:
	struct mmc_data data = {0};

because it's shorter, as performant, and easier to work out whether
initialization has happened.

Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 93a7efc..fb387c8 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -261,7 +261,7 @@
 
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	unsigned int timeout_us;
 
 	struct scatterlist sg;
@@ -282,8 +282,6 @@
 	cmd.arg = 0;
 	cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
 
-	memset(&data, 0, sizeof(struct mmc_data));
-
 	data.timeout_ns = card->csd.tacc_ns * 100;
 	data.timeout_clks = card->csd.tacc_clks * 100;
 
diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
index 95c298f..f44762b 100644
--- a/drivers/mmc/card/mmc_test.c
+++ b/drivers/mmc/card/mmc_test.c
@@ -249,12 +249,11 @@
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
 	struct mmc_command stop = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 
 	struct scatterlist sg;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
@@ -732,10 +731,9 @@
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
 	struct mmc_command stop = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
@@ -760,12 +758,11 @@
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
 	struct mmc_command stop = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 
 	struct scatterlist sg;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index de4e185..1ed3866 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -235,7 +235,7 @@
 {
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	struct scatterlist sg;
 	void *data_buf;
 
@@ -247,7 +247,6 @@
 		return -ENOMEM;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
@@ -459,7 +458,7 @@
 {
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	struct scatterlist sg;
 	u8 *data_buf;
 	u8 *test_buf;
@@ -489,7 +488,6 @@
 		memcpy(data_buf, test_buf, len);
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
diff --git a/drivers/mmc/core/sd_ops.c b/drivers/mmc/core/sd_ops.c
index dfe9a9c..8023f58 100644
--- a/drivers/mmc/core/sd_ops.c
+++ b/drivers/mmc/core/sd_ops.c
@@ -245,7 +245,7 @@
 	int err;
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	struct scatterlist sg;
 	void *data_buf;
 
@@ -267,7 +267,6 @@
 		return -ENOMEM;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
@@ -307,7 +306,7 @@
 {
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	struct scatterlist sg;
 
 	BUG_ON(!card);
@@ -319,7 +318,6 @@
 	value &= 0xF;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
@@ -355,7 +353,7 @@
 	int err;
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	struct scatterlist sg;
 
 	BUG_ON(!card);
@@ -369,7 +367,6 @@
 		return err;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;
diff --git a/drivers/mmc/core/sdio_ops.c b/drivers/mmc/core/sdio_ops.c
index f77b1bc..147dfc1 100644
--- a/drivers/mmc/core/sdio_ops.c
+++ b/drivers/mmc/core/sdio_ops.c
@@ -123,7 +123,7 @@
 {
 	struct mmc_request mrq;
 	struct mmc_command cmd = {0};
-	struct mmc_data data;
+	struct mmc_data data = {0};
 	struct scatterlist sg;
 
 	BUG_ON(!card);
@@ -137,7 +137,6 @@
 		return -EINVAL;
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
-	memset(&data, 0, sizeof(struct mmc_data));
 
 	mrq.cmd = &cmd;
 	mrq.data = &data;