arm64: defconfig: Enable WIFI and BT LED trigger events

For WIFI(yellow) LED, available triggers are phy0rx, phy0tx,
phy0assoc, phy0radio and rfkill0. Appropriate trigger could
be activated with:

echo phy0assoc > /sys/class/leds/apq8016-sbc\:yellow\:wifi/trigger

For Bluetooth(blue) LED available trigger is rfkill1, which
could be activated with:

echo rfkill1 > /sys/class/leds/apq8016-sbc\:blue\:bt/trigger

Signed-off-by: Ivan T. Ivanov <ivan.ivanov@linaro.org>
[nicolas.dechesne@linaro.org: move CONFIGs changes to distro.config instead]
Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>