ext4: use WARN in ext4_alloc_blocks

Use WARN rather than printk followed by WARN_ON(1), for conciseness.

A simplified version of the semantic patch that makes this transformation
is as follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression list es;
@@

-printk(
+WARN(1,
  es);
-WARN_ON(1);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/indirect.c

@@ -358,9 +358,8 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
 			 * for the first direct block
 			 */
 			new_blocks[index] = current_block;
-			printk(KERN_INFO "%s returned more blocks than "
+			WARN(1, KERN_INFO "%s returned more blocks than "
 						"requested\n", __func__);
-			WARN_ON(1);
 			break;
 		}
 	}