net: make ->{get,set}sockopt in proto_ops optional

Just check for a NULL method instead of wiring up
sock_no_{get,set}sockopt.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -4503,8 +4503,6 @@ static const struct proto_ops packet_ops_spkt = {
 	.gettstamp =	sock_gettstamp,
 	.listen =	sock_no_listen,
 	.shutdown =	sock_no_shutdown,
-	.setsockopt =	sock_no_setsockopt,
-	.getsockopt =	sock_no_getsockopt,
 	.sendmsg =	packet_sendmsg_spkt,
 	.recvmsg =	packet_recvmsg,
 	.mmap =		sock_no_mmap,