Initialize ccb_xs to NULL when taking a ccb off the free list. This prevents calling xs->done() for internal commands that don't have an xs associated with them. In turn, this prevents crashes when calling ciss_sync(), e.g. when rebooting.
Initialize ccb_xs to NULL when taking a ccb off the free list. This
prevents calling xs->done() for internal commands that don't have an
xs associated with them. In turn, this prevents crashes when calling
ciss_sync(), e.g. when rebooting.

Reported on misc@ by Peter Huncar.

Prodded by kettenis@, halex@ and johan@. Fix tested by halex@.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars