iavf: Rework mutexes for better synchronisation

The driver used to crash in multiple spots when put to stress testing
of the init, reset and remove paths.

The user would experience call traces or hangs when creating,
resetting, removing VFs. Depending on the machines, the call traces
are happening in random spots, like reset restoring resources racing
with driver remove.

Make adapter->crit_lock mutex a mandatory lock for guarding the
operations performed on all workqueues and functions dealing with
resource allocation and disposal.

Make __IAVF_REMOVE a final state of the driver respected by
workqueues that shall not requeue, when they fail to obtain the
crit_lock.

Make the IRQ handler not to queue the new work for adminq_task
when the __IAVF_REMOVE state is set.

Fixes: 5ac49f3c ("iavf: use mutexes for locking of critical sections")
Signed-off-by: Slawomir Laba <slawomirx.laba@intel.com>
Signed-off-by: Phani Burra <phani.r.burra@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>