dm: disk: Use legacy block driver info for block device access

Instead of calling xx_get_dev() functions for each interface type, use the
new legacy block driver which can provide the device through its interface.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/disk/part.c b/disk/part.c
index 2613bff..f055c74 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -72,7 +72,6 @@
 static struct blk_desc *get_dev_hwpart(const char *ifname, int dev, int hwpart)
 {
 	const struct block_drvr *drvr = block_drvr;
-	struct blk_desc* (*reloc_get_dev)(int dev);
 	int (*select_hwpart)(int dev_num, int hwpart);
 	char *name;
 	int ret;
@@ -86,16 +85,16 @@
 #endif
 	while (drvr->name) {
 		name = drvr->name;
-		reloc_get_dev = drvr->get_dev;
 		select_hwpart = drvr->select_hwpart;
 #ifdef CONFIG_NEEDS_MANUAL_RELOC
 		name += gd->reloc_off;
-		reloc_get_dev += gd->reloc_off;
 		if (select_hwpart)
 			select_hwpart += gd->reloc_off;
 #endif
 		if (strncmp(ifname, name, strlen(name)) == 0) {
-			struct blk_desc *dev_desc = reloc_get_dev(dev);
+			struct blk_desc *dev_desc;
+
+			dev_desc = blk_get_devnum_by_typename(name, dev);
 			if (!dev_desc)
 				return NULL;
 			if (hwpart == 0 && !select_hwpart)