net: sock: remove the unnecessary check in proto_register

tw_prot_cleanup will check the twsk_prot.

Fixes: 0f5907af ("net: Fix potential memory leak in proto_register()")
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -3531,7 +3531,7 @@ int proto_register(struct proto *prot, int alloc_slab)
 	return ret;
 
 out_free_timewait_sock_slab:
-	if (alloc_slab && prot->twsk_prot)
+	if (alloc_slab)
 		tw_prot_cleanup(prot->twsk_prot);
 out_free_request_sock_slab:
 	if (alloc_slab) {