drm: add connector info/property for non-desktop displays [v2]

This adds the infrastructure needed to quirk displays
using edid and to mark them a non-desktop.

A non-desktop display is one which shouldn't normally be included
as a part of a desktop environment.

This is meant to cover head mounted devices like HTC Vive.

v2: Change description from non-standard to non-desktop, add docs

Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

fixup docs

include/drm/drm_connector.h

@@ -284,6 +284,11 @@ struct drm_display_info {
 	 * @hdmi: advance features of a HDMI sink.
 	 */
 	struct drm_hdmi_info hdmi;
+
+	/**
+	 * @non_desktop: Non desktop display (HMD).
+	 */
+	bool non_desktop;
 };
 
 int drm_display_info_set_bus_formats(struct drm_display_info *info,