mxge: Sync w/ FreeBSD

mxge: Sync w/ FreeBSD

- Update firmware
- Sync w/ FreeBSD if_mxge.c rev 254263

Local changes:
- Adjust output path a little bit:
  o  Utilize bus_dmamap_load_mbuf_defrag()
  o  Utilize the header length fields in mbuf pkthdr instead of
     peeking at the packet data
- Change TSO mode to NDIS mode
- Minor white space changes
- Nuke mxge_lro.c; we won't need it