MFC r217353:

MFC r217353:
  - Add a locked variant of jme_start() and invoke it directly while holding
    the lock instead of queueing it to a task.
  - Do not invoke jme_rxintr() to reclaim any unprocessed but received
    packets when shutting down the interface.  Instead, just drop these
    packets to match the behavior of other drivers.
  - Hold the driver lock in the interrupt handler to avoid races with
    ioctl requests to down the interface.

git-svn-id: svn://svn.freebsd.org/base/stable/8@218866 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f