drm/i915/cdclk: Convert CDCLK code to intel_display

struct intel_display will replace struct drm_i915_private as
the main thing for display code. Convert the CDCLK code to
use it (as much as possible at this stage).

v2: Add local 'display' variable to __intel_display_device_info_runtime_init() (Jani)
    Simplify the to_intel_display(crtc_state) stuff (Jani)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240906143306.15937-3-ville.syrjala@linux.intel.com


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>