xfs: Fix default ASSERT in xfs_attr_set_iter

This ASSERT checks for the state value of RM_SHRINK in the set path
which should never happen.  Change to ASSERT(0);
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

fs/xfs/libxfs/xfs_attr.c

@@ -612,7 +612,7 @@ xfs_attr_set_iter(
 		error = xfs_attr_node_addname_clear_incomplete(dac);
 		break;
 	default:
-		ASSERT(dac->dela_state != XFS_DAS_RM_SHRINK);
+		ASSERT(0);
 		break;
 	}
 out: