Add transparency to incoming call screen
Phone: Disable accelerometer sensor while in-call and screen UI is off

During an active ongoing call, on targets that support proximity
sensors, there is an approximate spike in the current waveform in the
order of 1 Hz. Krait is woken up frequently by the sensors even when
the Screen UI is off while in-call. This fix ensures that by disabling
the listener in such a scenario (In-Call + Screen UI turned off) there
is no spike in power consumption.

Conflicts:

	src/com/android/phone/PhoneGlobals.java