spl: blk_fs: Fix uninitialized return value when we can't get a blk_desc

Initialize ret to avoid returning garbage if blk_get_devnum_by_uclass_id
fails.

Fixes: 8ce6a2e175 ("spl: blk: Support loading images from fs")
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

common/spl/spl_blk_fs.c

@@ -50,7 +50,7 @@ int spl_blk_load_image(struct spl_image_info *spl_image,
 	struct blk_desc *blk_desc;
 	loff_t actlen, filesize;
 	struct blk_dev dev;
-	int ret;
+	int ret = -ENODEV;
 
 	blk_desc = blk_get_devnum_by_uclass_id(uclass_id, devnum);
 	if (!blk_desc) {