libxfs: add missing agfl free deferred op type

libxfs: add missing agfl free deferred op type

When we added a new defer op type for agfl block freeing to the kernel,
we forgot to add that type to the userspace side of things.  This will
cause spontaneous combustion in xfs_repair if we try to rebuild
directories.

Fixes: d5c1b462232 ("xfs: defer agfl block frees when dfops is available")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>