xfs: xfs_bmapi_read doesn't take a fork id as the last argument

The last argument to xfs_bmapi_raad contains XFS_BMAPI_* flags, not the
fork.  Given that XFS_DATA_FORK evaluates to 0 no real harm is done,
but let's fix this anyway.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_rtbitmap.c

@@ -66,7 +66,7 @@ xfs_rtbuf_get(
 
 	ip = issum ? mp->m_rsumip : mp->m_rbmip;
 
-	error = xfs_bmapi_read(ip, block, 1, &map, &nmap, XFS_DATA_FORK);
+	error = xfs_bmapi_read(ip, block, 1, &map, &nmap, 0);
 	if (error)
 		return error;