drm: Fix the kernel doc warning for drm_link_status

This fixes the kernel doc warning that was introduced in
the 'commit 40ee6fb ("drm: Add a new connector
atomic property for link status")'. Description has
been added for the enum values.

Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1488379510-15059-1-git-send-email-manasi.d.navare@intel.com

include/drm/drm_connector.h

@@ -94,6 +94,11 @@ enum subpixel_order {
  *
  * This enum is used as the connector's link status property value.
  * It is set to the values defined in uapi.
+ *
+ * @DRM_LINK_STATUS_GOOD: DP Link is Good as a result of successful
+ *                        link training
+ * @DRM_LINK_STATUS_BAD: DP Link is BAD as a result of link training
+ *                       failure
  */
 enum drm_link_status {
 	DRM_LINK_STATUS_GOOD = DRM_MODE_LINK_STATUS_GOOD,