wlcore: fix zeroing out of tx aggr stats (DEBUG)

Before only a pointer was zeroed, giving little effect.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
wlcore: correctly check state before regdomain conf

The wlcore state was checked without the mutex being taken. This leads
to WARN_ONs sometimes if a notification arrives when the driver
is on, but the mutex is only taken after it is off. This usually
happens if stopping the driver while connected to a network.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
wlcore: consider dummy packets when tx queues are empty

Don't ignore dummy packets when our queues are empty. This causes dummy
packets never to be sent when traffic is not suspended by FW thresholds,
which happens only in high Tx throughput situations. This may hurt Rx
performance.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Ido Yariv <ido@wizery.com>