Use the proper LED driver on the Libra (#5416)

So that we can actually set the warmth ;)

frontend/device/kobo/device.lua

@@ -250,7 +250,7 @@ local KoboStorm = Kobo:new{
     hasNaturalLight = yes,
     frontlight_settings = {
         frontlight_white = "/sys/class/backlight/mxc_msp430.0/brightness",
-        frontlight_mixer = "/sys/class/backlight/tlc5947_bl/color",
+        frontlight_mixer = "/sys/class/backlight/lm3630a_led/color",
         -- Warmth goes from 0 to 10 on the device's side (our own internal scale is still normalized to [0...100])
         -- NOTE: Those three extra keys are *MANDATORY* if frontlight_mixer is set!
         nl_min = 0,