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/common/spl/spl_mmc.c b/common/spl/spl_mmc.c
index 8d588d1..cf527da 100644
--- a/common/spl/spl_mmc.c
+++ b/common/spl/spl_mmc.c
@@ -296,7 +296,7 @@
 			if (part == 7)
 				part = 0;
 
-			err = mmc_switch_part(0, part);
+			err = blk_dselect_hwpart(mmc_get_blk_desc(mmc), part);
 			if (err) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
 				puts("spl: mmc partition switch failed\n");