mmc: mmcblk: Add support for deferred SD bus resume

Signed-off-by: San Mehat <san@google.com>

mmc: card: Add MMC_BLOCK_DEFERRED_RESUME option to Kconfig

Signed-off-by: San Mehat <san@google.com>
diff --git a/drivers/mmc/card/Kconfig b/drivers/mmc/card/Kconfig
index 3b1f783..ebb4afe 100644
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -50,6 +50,15 @@
 
 	  If unsure, say Y here.
 
+config MMC_BLOCK_DEFERRED_RESUME
+	bool "Deferr MMC layer resume until I/O is requested"
+	depends on MMC_BLOCK
+	default n
+	help
+	  Say Y here to enable deferred MMC resume until I/O
+	  is requested. This will reduce overall resume latency and
+	  save power when theres an SD card inserted but not being used.
+
 config SDIO_UART
 	tristate "SDIO UART/GPS class support"
 	help