Sync with FreeBSD dev/xe

Sync with FreeBSD dev/xe

if_xe.c		1.39
if_xe_pccard	1.11
if_xereg.h	1.6
if_xevar.h	1.4
Major update to xe driver: (*)
- Make multicast work
- Fix (some of) the watchdog timeouts after card reset
- Add support for CE2, CEM28 and CEM33 cards
- General code cleanup

if_xe.c		1.42
if_xe_pccard.c	1.14
- Add hw.xe.debug sysctl node, set it to 1 by default
- Turn XE_DEBUG on by default

(*) This update was submitted to FreeBSD by
    Scott Mitchell <scott+freebsd at fishballoon.org>