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_mode_config.h

@@ -728,6 +728,13 @@ struct drm_mode_config {
 	 */
 	struct drm_property *suggested_y_property;
 
+	/**
+	 * @non_desktop_property: Optional connector property with a hint
+	 * that device isn't a standard display, and the console/desktop,
+	 * should not be displayed on it.
+	 */
+	struct drm_property *non_desktop_property;
+
 	/* dumb ioctl parameters */
 	uint32_t preferred_depth, prefer_shadow;