igc: Add Host Good Packets Transmitted Count

This counter counts the number of good (non-erred) packets
transmitted sent by the host.
A good transmit packet is considered one that is 64 or more bytes
in length (from <Destination Address> through <CRC>,
inclusively) in length

Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>