Sync with FreeBSD dev/em

Sync with FreeBSD dev/em

if_em.c		rev 1.2.2.{20,21,22} 1.47 1.63
if_em.h		rev 1.1.2.17
if_em_hw.c	rev 1.1.2.12
if_em_hw.h	rev 1.1.2.12

- Add support for Intel PRO/1000 GT Desktop Adapter
- Add support for Intel 82546GB dual port PCIE adapter
- Add fix for 82547 which corrects an issue with Jumbo frames larger than 10k
- Add fix for vlan tagged frames not being properly bridged
- Correct TBI workaround
- Correct LED operation issues
- Do not count RNBC (internal buffer full) towards the RX error count,
  since it's not really an error
- Correct a workaround that should only be applied to one adapter.  Workaround
  was causing device hangs when incorrectly applied to other adapters (*)
- Run em_local_timer() once per second instead of running it once per 2 seconds.
  This makes gathering of stats more precise

(*) Detailed problem description is in FreeBSD's PR kern/66634