overlay: fw: increase brightness arrays

* Stock brightness arrays just don't cut it on aosp. Its too dim
  at low lux readings
* Add more cowbell

Change-Id: I64b8edb38bdab3a06e8aaaeb521d1f2c5ee9b3e7
BoardConfig: use linaro-4.9_a15 for kernel

Change-Id: Icaaaf81de645daf98a5efffb9efa32190760208f