net: ethernet: Fix length update for unsupported packet families

Do not update packet length for unsupported packet families.
AF_PACKET family used the IPv6 length update, which breaks the
packet length if there is a payload with bytes resembling a
IPv6 length field less then 6 or a IPv4 length field less
then 46.

Signed-off-by: Christoph Seitz <christoph.seitz@infineon.com>
1 file changed