PacketBuilder: correct IPv6 header payload length

Ipv6 payload length doesn't include header length.

rfc8200 section 3
https://tools.ietf.org/html/rfc8200
Payload Length      16-bit unsigned integer. Length of the IPv6
                    payload, i.e., the rest of the packet
                    following this IPv6 header, in octets.

Bug: 215655463
Test: atest NetworkStaticLibTests
Change-Id: Ifdc871125b0fe2eb3a8909b8b0723a62dbe44bcf
2 files changed
tree: a289a25ebc86bf77226db9dfd84745546a3b1608
  1. staticlibs/