linux-wandboard

drm/i915: add aux_ch_ctl_reg to struct intel_dp

This way we can remove some duplicated code and avoid more mistakes
and regressions with these registers in the future.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>