drm/i915/dpt: Introduce HAS_DPT()

Replace the hand rolled DISPLAY_VER check for a more descriptive
HAS_DPT() macro. Will be used on more than one place later.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230320090522.9909-4-ville.syrjala@linux.intel.com


Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>