netinet/tcp.h: add tcp zerocopy related changes from linux v5.11

see

  linux commit 18fb76ed53865c1b5d5f0157b1b825704590beb5
  net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.

  linux commit 94ab9eb9b234ddf23af04a4bc7e8db68e67b8778
  net-zerocopy: Defer vm zap unless actually needed.

include/netinet/tcp.h

@@ -281,12 +281,17 @@ struct tcp_repair_window {
 	uint32_t rcv_wup;
 };
 
+#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
+
 struct tcp_zerocopy_receive {
 	uint64_t address;
 	uint32_t length;
 	uint32_t recv_skip_hint;
 	uint32_t inq;
 	int32_t err;
+	uint64_t copybuf_address;
+	int32_t copybuf_len;
+	uint32_t flags;
 };
 
 #endif