dm: mmc: Use the new select_hwpart() API

Avoid calling directly into the MMC code - use the new API call instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 49996a8..7322f334 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -257,7 +257,7 @@
 	if (!mmc)
 		return 0;
 
-	err = mmc_select_hwpart(dev_num, block_dev->hwpart);
+	err = blk_dselect_hwpart(block_dev, block_dev->hwpart);
 	if (err < 0)
 		return 0;