RIL: mark mInstanceId as protected

To use in RIL subclasses

Change-Id: I4ab1ea79079e3b03670b1e985f7a574df1f16658
RIL: set responseCellInfoList protected to override in sub classes

Change-Id: Ibbbee0c1a59ab2be6b71fc2f70c6279314b55d6e