mmc: sdhci_pltfm: Constify sdhci_pltfm_data

The sdhci_pltfm_data struct is never modified within the sdhci_pltfm
module. So make the pdata parameter to sdhci_pltfm_init and
sdhci_pltfm_register const.  This allows drivers to declare their
sdhci_pltfm_data struct as const.

This patch also makes the sdhci_pltfm_data declarations const where
possible.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci-dove.c b/drivers/mmc/host/sdhci-dove.c
index 169fab9..b514f68 100644
--- a/drivers/mmc/host/sdhci-dove.c
+++ b/drivers/mmc/host/sdhci-dove.c
@@ -88,7 +88,7 @@
 	.read_l	= sdhci_dove_readl,
 };
 
-static struct sdhci_pltfm_data sdhci_dove_pdata = {
+static const struct sdhci_pltfm_data sdhci_dove_pdata = {
 	.ops	= &sdhci_dove_ops,
 	.quirks	= SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER |
 		  SDHCI_QUIRK_NO_BUSY_IRQ |