drm/i915: Pass crtc state to i9xx_enable_pll()

Pass the crtc state to i9xx_enable_pll() and use it rather than
crtc->config.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170913140900.6972-5-ville.syrjala@linux.intel.com


Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>