drm: Add missing DP downstream port types

Add missing DisplayPort downstream port types. The introduced
new port types are DP++ and Wireless.

Reviewed-by: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1473419458-17080-2-git-send-email-mika.kahola@intel.com

include/drm/drm_dp_helper.h

@@ -211,6 +211,8 @@
 # define DP_DS_PORT_TYPE_DVI		    2
 # define DP_DS_PORT_TYPE_HDMI		    3
 # define DP_DS_PORT_TYPE_NON_EDID	    4
+# define DP_DS_PORT_TYPE_DP_DUALMODE        5
+# define DP_DS_PORT_TYPE_WIRELESS           6
 # define DP_DS_PORT_HPD			    (1 << 3)
 /* offset 1 for VGA is maximum megapixels per second / 8 */
 /* offset 2 */