libxfs: Fix a couple of sparse complaintis

No significant changes, just silence a couple of sparse errors.

Using cpu_to_be32(NULLAGINO), the NULLAGINO constant will be encoded in
BE as a constant, avoiding a BE -> CPU conversion every iteraction of
the loop, if be32_to_cpu(agi->agi_unlinked[i]) was used instead.
Signed-off-by: NCarlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: NBill O'Donnell <billodo@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_ag_resv.h

@@ -28,7 +28,7 @@ xfs_ag_resv_rmapbt_alloc(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agno)
 {
-	struct xfs_alloc_arg	args = {0};
+	struct xfs_alloc_arg	args = { NULL };
 	struct xfs_perag	*pag;
 
 	args.len = 1;

fs/xfs/libxfs/xfs_ialloc.c

@@ -2537,7 +2537,7 @@ xfs_agi_verify(
 		return __this_address;
 
 	for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++) {
-		if (agi->agi_unlinked[i] == NULLAGINO)
+		if (agi->agi_unlinked[i] == cpu_to_be32(NULLAGINO))
 			continue;
 		if (!xfs_verify_ino(mp, be32_to_cpu(agi->agi_unlinked[i])))
 			return __this_address;