drm/i915/bios: Define VBT block 4 (Mode Support List) contents

drm/i915/bios: Define VBT block 4 (Mode Support List) contents

Define the contents of VBT block 4 (Mode Support List).

Slightly crazy layout with a variable length list at the start,
followed by the length of said list.

No real idea what these "Intel mode numbers" really are. What
I see in real world VBTs seems to be always the same list of
26 numbers, ranging between 0x30 and 0x84.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503122449.27266-11-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>