ath9k: Fix queue handling for channel contexts

When a full chip reset is done, all the queues
across all VIFs are stopped, but if MCC is enabled,
only the queues of the current context is awakened,
when we complete the reset.

This results in unfairness for the inactive context.
Since frames are queued internally in the driver if
there is a context mismatch, we can awaken all the
queues when coming out of a reset.

The VIF-specific queues are still used in flow control,
to ensure fairness when traffic is high.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>