staging: wfx: drop useless sta_asleep_mask

staging: wfx: drop useless sta_asleep_mask

Currently, the driver tracks power save state of the stations with the
variable sta_asleep_mask. Then, it takes care to not sent data to asleep
stations.

However, this work is already done by mac80211. Normally, there are no
frames for asleep stations in our queues. So, driver do not have to
filter frames in its queues (apart the frames marked "AFTER_DTIM").

Notice that there is a risk of race between state of the station and
data send to the firmware. However, this risk is limited since the
number of frame in queues are small. In add, this race also exists with
the current code. Anyway, the firmware is able to detect the problem and
driver will receive a 'REQUEUE' status (translated in
TX_STAT_TX_FILTERED for mac80211).

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200401110405.80282-13-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>