iwlwifi: virtualize command queue full behaviour

When the command queue is full, the transport
will return -ENOSPC, but the reaction to that
depends on the op_mode. Virtualize that, the
DVM op_mode checks for CT-kill and restarts
the hardware otherwise.

We may be able to get rid of this callback by
putting the behaviour check into the wrapper
but that needs more careful evaluation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>