mmc: core: Add in support to expose PRV for v4 MMCs

The JEDEC MMC v4 spec defines a new PRV value in place of the original
fwrev and hwrev specified in v1. We can expose this in the kernel to enable
user space to more easily determine the product revision of a given MMC.

Signed-off-by: Bernie Thompson <bhthompson@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 61b2c30..f31725b 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -17,6 +17,7 @@
 struct mmc_cid {
 	unsigned int		manfid;
 	char			prod_name[8];
+	unsigned char		prv;
 	unsigned int		serial;
 	unsigned short		oemid;
 	unsigned short		year;