dm: blk: Fix get_desc to return block device descriptor

Current get_desc() implementation is not able to succesfully
finish and return pointer to block device descriptor.

Also function always return non zero value even device is found.

The patch fills block device descriptor and return 0 if device is found.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/block/blk-uclass.c

@@ -156,6 +156,8 @@ static int get_desc(enum if_type if_type, int devnum, struct blk_desc **descp)
 				if (ret)
 					return ret;
 
+				*descp = desc;
+				return 0;
 			} else if (desc->devnum > devnum) {
 				found_more = true;
 			}