mmc: core: Modify the timeout value for writing power class

This patch will apply the generic CMD6 timeout to switch command
for power class.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/mmc.c

@@ -663,7 +663,7 @@ static int mmc_select_powerclass(struct mmc_card *card,
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_POWER_CLASS,
 				 pwrclass_val,
-				 0);
+				 card->ext_csd.generic_cmd6_time);
 	}
 
 	return err;