drm/i915: rewrite hsw/bdw audio codec enable/disable sequences
drm/i915: rewrite hsw/bdw audio codec enable/disable sequences

There's some serious confusion regarding ELD valid bit that gets set and
cleared back and forth etc. Rewrite it all based on the documented audio
codec enable/disable sequences.

v3: replace vblank wait with a comment

v4: expand the comment on what should be done with the vblank wait

Signed-off-by: Jani Nikula <ba783f3beccaedfda693f41a15407d612a629408@intel.com>
Reviewed-by: Rodrigo Vivi <f714145d6ee82178e54021e0c168f56d17b53c9c@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs