drm/i915: Abstract display info away during probe

The goal is to have this function ready for Xe to use
directly. So, let's use the available macro.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230929205023.1202735-1-rodrigo.vivi@intel.com