Separate the parsing of display info and modes from the CTA
Y420VDB. This is prerequisite work for overall better separation of the
two parsing steps.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3bc5fe6650a6ce4249803f7192096764ea724e05.1672826282.git.jani.nikula@intel.com