mmc: Add function declarations for mmc_bread() and mmc_switch_part()

These private functions are used both in the driver-model implementation and
in the legacy code. Add them to the header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index aabfc71..a27fcb4 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -215,11 +215,10 @@
 }
 
 #ifdef CONFIG_BLK
-static ulong mmc_bread(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
-		       void *dst)
+ulong mmc_bread(struct udevice *dev, lbaint_t start, lbaint_t blkcnt, void *dst)
 #else
-static ulong mmc_bread(struct blk_desc *block_dev, lbaint_t start,
-		       lbaint_t blkcnt, void *dst)
+ulong mmc_bread(struct blk_desc *block_dev, lbaint_t start, lbaint_t blkcnt,
+		void *dst)
 #endif
 {
 #ifdef CONFIG_BLK
@@ -566,7 +565,7 @@
 	return 0;
 }
 
-static int mmc_switch_part(struct mmc *mmc, unsigned int part_num)
+int mmc_switch_part(struct mmc *mmc, unsigned int part_num)
 {
 	int ret;