Radio Capability Support.

New design of capability switch for L.
Add new RIL requests:
     RIL_REQUEST_GET_RADIO_CAPABILITY
     RIL_REQUEST_SET_RADIO_CAPABILITY
     RIL_UNSOL_RADIO_CAPABILITY

These commands allow the framework to communicate what the Radio
Capabilities for each logical modem has or should be using.

It can support 2/3/4G switch and has flexible architecture to support
future technology.

Change-Id: Iedf7f608d2ba3c06a883500f2d85abb98e69d9c1