net: remove sock_no_poll

Now that sock_poll handles a NULL ->poll or ->poll_mask there is no need
for a stub.

Signed-off-by: Christoph Hellwig <hch@lst.de>

net/bluetooth/hidp/sock.c

@@ -208,7 +208,6 @@ static const struct proto_ops hidp_sock_ops = {
 	.getname	= sock_no_getname,
 	.sendmsg	= sock_no_sendmsg,
 	.recvmsg	= sock_no_recvmsg,
-	.poll		= sock_no_poll,
 	.listen		= sock_no_listen,
 	.shutdown	= sock_no_shutdown,
 	.setsockopt	= sock_no_setsockopt,