cypress-touchkey: remove backlight timeout feature

Userspace implementation:
http://review.cyanogenmod.org/48796
http://review.cyanogenmod.org/48872
http://review.cyanogenmod.org/48884

Change-Id: Id4ac50168220310e82aa4aae367dad4e72e3a9c3
cypress-touchkey: remove backlight timeout feature
Merge remote-tracking branch 'CM/cm-10.2' into cm-10.2