[XFS] Check return value of xfs_buf_get_noaddr()

We check the return value of all other calls to xfs_buf_get_noaddr().
Make sense to do it here too.
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>

fs/xfs/xfs_vnodeops.c

@@ -3034,6 +3034,8 @@ xfs_zero_remaining_bytes(
 	bp = xfs_buf_get_noaddr(mp->m_sb.sb_blocksize,
 				XFS_IS_REALTIME_INODE(ip) ?
 				mp->m_rtdev_targp : mp->m_ddev_targp);
+	if (!bp)
+		return XFS_ERROR(ENOMEM);
 
 	for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
 		offset_fsb = XFS_B_TO_FSBT(mp, offset);