net: openvswitch: add missing .resv_start_op

I missed one of the families in OvS when annotating .resv_start_op.
This triggers the warning added in commit ce48ebdd ("genetlink:
limit the use of validation workarounds to old ops").

Reported-by: syzbot+40eb8c0447c0e47a7e9b@syzkaller.appspotmail.com
Fixes: 9c5d03d3 ("genetlink: start to validate reserved header bytes")
Link: https://lore.kernel.org/r/20221028032501.2724270-1-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/openvswitch/datapath.c

@@ -2544,6 +2544,7 @@ struct genl_family dp_vport_genl_family __ro_after_init = {
 	.parallel_ops = true,
 	.small_ops = dp_vport_genl_ops,
 	.n_small_ops = ARRAY_SIZE(dp_vport_genl_ops),
+	.resv_start_op = OVS_VPORT_CMD_SET + 1,
 	.mcgrps = &ovs_dp_vport_multicast_group,
 	.n_mcgrps = 1,
 	.module = THIS_MODULE,