xfs: fix I_DONTCACHE

Yup, the VFS hoist broke it, and nobody noticed. Bulkstat workloads
make it clear that it doesn't work as it should.

Fixes: dae2f8ed7992 ("fs: Lift XFS_IDONTCACHE to the VFS layer")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 0ff0cca..a607d6a 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1344,7 +1344,7 @@ xfs_setup_inode(
 	gfp_t			gfp_mask;
 
 	inode->i_ino = ip->i_ino;
-	inode->i_state = I_NEW;
+	inode->i_state |= I_NEW;
 
 	inode_sb_list_add(inode);
 	/* make the inode look hashed for the writeback code */