xfs: always set rvalp in xfs_dir2_node_trim_free

xfs_dir2_node_trim_free can return with setting the rvalp argument
pointer.  Initialize it to 0 at the beginning of the function and
only update it to 1 if we succeeded trimming a freespace block.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NCarlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_dir2_node.c

@@ -2235,6 +2235,9 @@ xfs_dir2_node_trim_free(
 
 	dp = args->dp;
 	tp = args->trans;
+
+	*rvalp = 0;
+
 	/*
 	 * Read the freespace block.
 	 */
@@ -2255,7 +2258,6 @@ xfs_dir2_node_trim_free(
 	 */
 	if (freehdr.nused > 0) {
 		xfs_trans_brelse(tp, bp);
-		*rvalp = 0;
 		return 0;
 	}
 	/*