mmc: core: Move calls to ->prepare_hs400_tuning() closer to mmc code

Move the calls to ->prepare_hs400_tuning(), from mmc_retune() into
mmc_hs400_to_hs200(), as it better belongs there, rather than being generic
to all type of cards.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 57a8bd3..4466f5d 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1282,6 +1282,10 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 
 	mmc_set_bus_speed(card);
 
+	/* Prepare tuning for HS400 mode. */
+	if (host->ops->prepare_hs400_tuning)
+		host->ops->prepare_hs400_tuning(host, &host->ios);
+
 	return 0;
 
 out_err: