Telephony: Implementation for IWLAN.

Introduce new RAT as IWLAN.
- Allow registration polling in airplane mode.
- Allow non-default PDP activation for iwlan RAT.

Implementation of iwlan and wwan coexistence.
- A new callback event for unsol oem hook response to indicate
  if cellular and iwlan RAT co-exists.
- If co-existence is possible then allow default PDP activation
  along with other PDPs.

Change-Id: Icc6f8111ec3c86ec06e8facd5a5b60b4d5e08e78