drm/i915/display: Enable HDR on gen9 devices with MCA Lspcon

Gen9 hardware supports HDMI2.0 through LSPCON chips.
Extending HDR support for MCA LSPCON based GEN9 devices.

SOC will drive LSPCON as DP and send HDR metadata as standard
DP SDP packets. LSPCON will be set to operate in PCON mode,
will receive the metadata and create Dynamic Range and
Mastering Infoframe (DRM packets) and send it to HDR capable
HDMI sink devices.

v2: Re-used hsw infoframe write implementation for HDR metadata
for LSPCON as per Ville's suggestion.

v3: Addressed Jani Nikula's review comments.

v4: Addressed Ville's review comments, removed redundant wrapper
and checks, passed arguments instead of hardcodings.

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/20201130204738.2443-3-uma.shankar@intel.com