msm8960-common: Add haptic feedback control prefs

add settings to control vibration intensity

Requires http://review.cyanogenmod.org/36175 http://review.cyanogenmod.org/36232

Change-Id: I042f3e79f2b1bd36968d0b4a5c128b30bbc6738d
Merge pull request #12 from CyanogenMod/cm-10.1

msm8960-common: Add haptic feedback control prefs