FreeBSD: add missing fplookup_vexec handler to special vop vectors

Otherwise lookup can fail with EOPNOTSUPP or panic.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Matt Macy <mmacy@FreeBSD.org>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Closes #11066

module/os/freebsd/zfs/zfs_vnops.c

@@ -6641,6 +6641,9 @@ VFS_VOP_VECTOR_REGISTER(zfs_fifoops);
  */
 struct vop_vector zfs_shareops = {
 	.vop_default =		&default_vnodeops,
+#if __FreeBSD_version >= 1300121
+	.vop_fplookup_vexec =	VOP_EAGAIN,
+#endif
 	.vop_access =		zfs_freebsd_access,
 	.vop_inactive =		zfs_freebsd_inactive,
 	.vop_reclaim =		zfs_freebsd_reclaim,