Telephony: Add getLteOnGsmMode() method (2/2)

Same functionality as the existing getLteOnCdmaMode, but for GSM
LTE devices.
Enable with the telephony.lteOnGsmDevice system property

From CM 10.0: Ibfb47ca608e51393b99d3308e0a6c66050b3f32e
- Moved getLteOnGsmModeStatic() to TelephonyManager.
Add notification type constants.

Change-Id: I3bafac72744d0e77436324db5aafec965ca2cd45
Allow registering for supplementary service notifications.

Change-Id: Id40d320cb6935ddf4cceefa8ddb42f9229b66efa
telephony: CdmaServiceStateTracker: Get cdma sub. when ruim ready.

This code made the assumption that cdma subscription isn't needed
when on cdma + lte. QCOM devices need to get both to provision
propertly because some SIM records are missing.

This patch adds a system property ro.cdma.subscribe_on_ruim_ready
to specify that CDMA subscription should be requested using NV
once the SIM records have been read.

Change-Id: I3e989e9f75c08412bb5f19155beea52e7d9f3c43