fix: remove unused variables res, cpu in tcp_ipv4.c patch

.github/actions/networking/patches/0001-net-tcp-backport-BBRv3-to-android14-5.15.patch

@@ -3135,7 +3135,7 @@ index ca3ffe46a..9df881f5d 100644
  static int __net_init tcp_sk_init(struct net *net)
  {
 -	int cnt;
-+	int res, cpu, cnt;
++	int cnt;
 +	struct tcp_plb_net_context *ctx, *init_ctx;
  
  	net->ipv4.sysctl_tcp_ecn = 2;