tcp: Use pI6c in tcp tracepoint

The compact form for IPv6 addresses is more user friendly than the full
version. For example:
   compact: 2001:db8:1::1
      full: 2001:0db8:0001:0000:0000:0000:0000:0004i

Update the tcp tracepoint to show the compact form.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>