drm/i915: Pass crtc state to DPIO PHY functions

Rather than digging through encoder->crtc and crtc->config in the
DPIO PHY functions, pass down the correct crtc state from the caller.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171031205123.13123-6-ville.syrjala@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>