MFC r216925,217331,217349,217542:

MFC r216925,217331,217349,217542:
r216925:
  Add a 'locked' variant of the foo_start() routine and call it directly
  from interrupt handlers and watchdog routines instead of queueing a task
  to call foo_start().

r217331:
  Make sure to invoke unlocked foo_start since the taskqueue does not
  hold a driver lock. This should fix a regression introduced in
  r216925.

r217349:
  Forgot to remove unlock of the driver lock from age_start_locked() when
  converting it to a locked variant.

r217542:
  Fix some bugs in my last set of changes to ale(4):
  - Remove extra unlock from end of ale_start_locked().
  - Expand scope of locking in interrupt handler.
  - Move ether_ifdetach() earlier and retire now-unneeded DETACH flag.

  Tested by:	Aryeh Friedman

git-svn-id: svn://svn.freebsd.org/base/stable/8@218198 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f