mmc: read ext_csd version number

Make sure we do not try to parse a structure we do not
understand.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index e3ed9b9..d1d6cbc 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -227,6 +227,7 @@
 #define EXT_CSD_BUS_WIDTH	183	/* R/W */
 #define EXT_CSD_HS_TIMING	185	/* R/W */
 #define EXT_CSD_CARD_TYPE	196	/* RO */
+#define EXT_CSD_REV		192	/* RO */
 #define EXT_CSD_SEC_CNT		212	/* RO, 4 bytes */
 
 /*