mmc: core: Use generic CMD6 time while switching to eMMC HS200 mode

Conform to the eMMC spec and use the CMD6 generic timeout from the
EXT_CSD register, when switching to HS200 mode.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index c944692..6b7ccef 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -857,7 +857,9 @@
 	/* switch to HS200 mode if bus width set successfully */
 	if (!err)
 		err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-				EXT_CSD_HS_TIMING, 2, 0, true, true, true);
+				EXT_CSD_HS_TIMING, 2,
+				card->ext_csd.generic_cmd6_time,
+				true, true, true);
 err:
 	return err;
 }