CEC: Avoid setting op in disabled mode

In disabled HDMI control mode, TV local device is gone, for which
setting operation is not possible. Does the check against the tv instance
when TV setting update is notified. The settings is picked up when
the control is enabled back, so notification is not lost.

Bug: 18580387
Change-Id: Id8891bfa54d851ec1aff280fc99be8e428f4e0cf