drm/i915/bios: group device type definitions together

No idea why some definitions were defined at a different place from the
rest. Move them together. No functional changes.

Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/6433a24240ef965f9c032e8f66fcce0ea33277ef.1503600621.git.jani.nikula@intel.com