xfs: fix typo in comment

Spelling mistake (triple letters) in comment.
Detected with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_symlink_remote.c

@@ -213,7 +213,7 @@ xfs_symlink_shortform_verify(
 
 	/*
 	 * Zero length symlinks should never occur in memory as they are
-	 * never alllowed to exist on disk.
+	 * never allowed to exist on disk.
 	 */
 	if (!size)
 		return __this_address;