wl1271: Decrease BET consecutive terminated beacons value to 10

Decrease the consecutive terminated beacons value for BET from 100 to 10.
According to the vendor, 10 will give a more reliable connection and more
reliable detection of connection problems.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>