[Trusty][PULL]: i915_bdw: backport an additional call for the audio driver to use

[Timo Aaltonen]

	Hi

  So the i915 & hda audio drivers have recently added a new call and we need to backport it to i915_bdw so that the audio stack can move forward:

git://kernel.ubuntu.com/tjaalton/ubuntu-trusty.git i915-bdw

a5810965b3bfec8 UBUNTU: SAUCE: drm/i915: provide interface for audio driver to query cdclk