Read value whether HDMI CEC is enabled from HdmiCecConfig and cache it
in HdmiControlService. This changes the type from boolean to int.
Adapt the @hide listener for a change of this value to return integers
instead of booleans as well.
Bug: 171870477
Test: atest com.android.server.hdmi
Change-Id: I6275fe1b3e1ca62c210019e1df216f8731a0b5ab