Introduce @ServiceThreadOnly and @IothreadOnly to HdmiControlService

Many of hdmi service modules assumes that it runs on
service thread without any lock. But it's a bit
hard to distinguish whether a method runs on
service thread or not even though there is run-time
assertion (runOnServiceThread()) is top of method.
@ServiceThreadOnly interface documents that a method should
run on service thread while @IoThreadOnly documents
that a method should run on io thread.

Change-Id: Ia4a6a48675d2302fb2cb7a8a807fcf112da5d4e7