drm/i915/display: Attach HDR property for capable Gen9 devices

drm/i915/display: Attach HDR property for capable Gen9 devices

Attach HDR property for Gen9 devices with MCA LSPCON
chips.

v2: Cleaned HDR property attachment logic based on capability
as per Jani Nikula's suggestion.

v3: Fixed the HDR property attachment logic as per the new changes
by Kai-Feng to align with lspcon detection failure on some devices.

v4: Add HDR proprty in late_register to handle lspcon detection,
as suggested by Ville.

v5: Init Lspcon only if advertized from BIOS.

v6: Added a Todo to plan a cleanup later, added Ville's RB.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201130204738.2443-4-uma.shankar@intel.com