clearCommunicationDevice only when necessary

Calling CallAudioRouteStateMachine#setSpeakerphoneOn(false)
clears communication device regardless of the current device,
which resulted in cancelling current BT communication device.

This CL fixes it.

Bug: 229342692
Test: atest CallAudioRouteStateMachineTest && manually confirmed
by calling.

Change-Id: I9ea8759fd89dce02c0c9d8ef49e7b547bb762c11