iwlwifi: pcie: poke device when commands don't complete quickly

In certain corner cases in the firmware implementation, powersave
transitions can cause the firmware to miss the fact that commands
were added to the queue/FIFO and thus never processes them. Since
the commands really are in the queue, try to poke the firmware in
such cases (by grabbing NIC access, which wakes up the NIC) so it
notices the new command and processes it.

Reviewed-by: Alexander Bondar <alexander.bondar@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>