Add Battery Life eXtender (BLX) - From MikeEx kernel_msm

This is a simple port of Ezekeel's BLX mod to the Nexus 4.

See this thread for more information:
http://forum.xda-developers.com/showthread.php?t=1257497

Let's keep the same sysfs implementation so that apps, such as Trickster
MOD, can support this.

matr1x-cm

https://github.com/MikeEx/kernel_msm/commit/dfbe00110b4d128c3e5c33dcff4fba034ed96c73