Fix HdmiCecLocalDevicePlaybackTest

Playback device implementation was unable to get an instance of
PowerManager to aquire the WakeLock that is acquired when the device is
active source.

Bug: 151147315
Test: atest HdmiCecLocalDevicePlaybackTest
Merged-In: I44a11d8d6365e32332818b08c84583c9afb5aa15
Change-Id: I44a11d8d6365e32332818b08c84583c9afb5aa15