turn on frontlight switch on Tolino. (#6586)

frontend/device/android/powerd.lua

@@ -75,6 +75,9 @@ function AndroidPowerD:turnOnFrontlightHW()
     if self:isFrontlightOn() and self:isFrontlightOnHW() then
         return
     end
+    -- on devices with a software frontlight switch (e.g Tolinos), enable it
+    android.enableFrontlightSwitch()
+
     android.setScreenBrightness(math.floor(self.fl_intensity * self.bright_diff / self.fl_max))
 
     self.is_fl_on = true