ath6kl: Fix bss filter setting while scanning

bss filter is configured to allow the frames from all the bss other
than the currenly connected one, this is done when a scan is requested
in connected state. There is no reason to filter out the currently
connected bss, configure the filter to allow all the bss. This would
fix the reporting of stale rssi of the current bss while scanning.

Reported-by: Naveen singh <navesing@qca.qualcomm.com>
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>