drm/i915: Pass dev_priv to remainder of the cdclk functions

Clean up the dev vs. dev_priv straggles that are making things
look inconsistentt.

v2: Deal with churn

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170120182205.8141-10-ville.syrjala@linux.intel.com