drm/i915/lspcon: Create separate infoframe_enabled helper

Lspcon has Infoframes as well as DIP for HDR metadata(DRM Infoframe).
Create a separate mechanism for lspcon compared to HDMI in order to
address the same and ensure future scalability.

v2: Streamlined this as per Ville's suggestions, making sure that
HDMI infoframe versions are directly returned instead of a redundant
and confusing DIP overhead.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
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/20201130204738.2443-12-uma.shankar@intel.com