xfs: xfs_btree_bload_prep_block() should use __GFP_NOFAIL

This was missed in the conversion from KM* flags.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 1063453 ("xfs: convert kmem_zalloc() to kzalloc()")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>

Author: Dave Chinner

fs/xfs/libxfs/xfs_btree_staging.c

@@ -303,7 +303,7 @@ xfs_btree_bload_prep_block(
 
 		/* Allocate a new incore btree root block. */
 		new_size = bbl->iroot_size(cur, level, nr_this_block, priv);
-		ifp->if_broot = kzalloc(new_size, GFP_KERNEL);
+		ifp->if_broot = kzalloc(new_size, GFP_KERNEL | __GFP_NOFAIL);
 		ifp->if_broot_bytes = (int)new_size;
 
 		/* Initialize it and send it out. */