init: Add a mechanism to extend the property service in device configs 

Instead of every so often adding a new set of stuff here for a specific
device, let the device includes overload the property arrays. The
new device_perms.h header documents it

Commit: https://github.com/CyanogenMod/android_system_core/commit/7e2d2c54abacb0bd9c85509d6f35b44fa50ad5d7