cec-compliance 'test-system-audio-control' fails

[gkoh]

There is one error:

	System Audio Control feature:
	    Request Short Audio Descriptor: OK (Not Supported)
	    Set System Audio Mode (directly addressed): OK (Presumed)
	    Set System Audio Mode (broadcast on): OK (Presumed)
	    System Audio Mode Status: OK (Unexpected)
	    System Audio Mode Request (on): OK (Unexpected)
	    Give System Audio Mode Status: OK (Unexpected)
	    Give Audio Status: OK (Unexpected)
	    User Control Pressed (Volume Up): OK (Presumed)
	    User Control Pressed (Volume Down): OK (Presumed)
	    User Control Pressed (Mute): OK (Presumed)
	    User Control Pressed (Restore Volume Function): OK (Presumed)
	    User Control Pressed (Mute Function): OK (Presumed)
	    User Control Released (Audio): OK (Presumed)
	    Set System Audio Mode (broadcast off): OK (Presumed)
		fail: cec-test-audio.cpp(960): status != CEC_OP_SYS_AUD_STATUS_OFF
	    System Audio Mode Request (off): FAIL

As we are not an audio device, the 'Unexpected' responses are expected.