libertas: fix cmdpendingq locking

libertas: fix cmdpendingq locking

commit 2ae1b8b35faba31a59b153cbad07f9c15de99740 upstream.

We occasionally see list corruption using libertas.

While we haven't been able to diagnose this precisely, we have spotted
a possible cause: cmdpendingq is generally modified with driver_lock
held. However, there are a couple of points where this is not the case.

Fix up those operations to execute under the lock, it seems like
the correct thing to do and will hopefully improve the situation.

Signed-off-by: Paul Fox <pgf@laptop.org>
Signed-off-by: Daniel Drake <dsd@laptop.org>
Acked-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>