drm/i915: s/cdclk_state/cdclk_config/

I want to have a higher level cdclk state object so let's rename
the current lower level thing to cdclk_config (because I lack
imagination).

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200120174728.21095-8-ville.syrjala@linux.intel.com


Reviewed-by: José Roberto de Souza <jose.souza@intel.com>