ath6kl: Enable force foreground scan in connected state

This was disabled beacause there was a network stall
issue when scan is issued. This issue does not happen
with the new firmware (3.1.1.609), enable it back.

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