mmc: core: add high-capacity erase size capability flag

Let drivers specify the use of high-capacity erase size.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index d7d8a93..02914d6 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -952,7 +952,8 @@
 	 * If enhanced_area_en is TRUE, host needs to enable ERASE_GRP_DEF
 	 * bit.  This bit will be lost every time after a reset or power off.
 	 */
-	if (card->ext_csd.enhanced_area_en) {
+	if (card->ext_csd.enhanced_area_en ||
+	    (card->ext_csd.rev >= 3 && (host->caps2 & MMC_CAP2_HC_ERASE_SZ))) {
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_ERASE_GROUP_DEF, 1,
 				 card->ext_csd.generic_cmd6_time);