dm: blk: Add a function to return the device type

Use the uclass name to get the device type for a block device.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/block/blk-uclass.c

@@ -509,6 +509,13 @@ int blk_get_from_parent(struct udevice *parent, struct udevice **devp)
 	return 0;
 }
 
+const char *blk_get_devtype(struct udevice *dev)
+{
+	struct udevice *parent = dev_get_parent(dev);
+
+	return uclass_get_name(device_get_uclass_id(parent));
+};
+
 int blk_find_max_devnum(enum if_type if_type)
 {
 	struct udevice *dev;