audio: Make platform_check_backends_match handle input devices as well

* The change 1d2a053f by Google introduced some additional checks
  before disabling audio routes, sadly these checks depend on
  platform_check_backends_match() supporting more than just
  output devices, which is a thing on Google's fork of QCOM
  audio HAL but not the CAF one.
* Without proper range checks, platform_check_backends_match()
  would pretty much always return false, preventing 'audio-record'
  usecase from being disabled during calls, which ends up breaking
  incall microphone when Google Assistant is listening.

Change-Id: Ifc923069a0e8eec68ff1e2faab432cdc30ca6ceb