drm/i915: Remove unused dp properties for dp-mst.

Those properties are not hooked up on MST and were ignored. Best not expose them at all.
Without this the next patch fails to start on X.org, because the DP-MST properties could
not be read.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/751b85a0-81cd-09e2-9e60-6d4ddbf1c6ac@linux.intel.com
Testcase: kms_properties
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 8389ed1..944b144 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5145,7 +5145,7 @@ bool intel_dp_is_edp(struct drm_i915_private *dev_priv, enum port port)
 	return intel_bios_is_port_edp(dev_priv, port);
 }
 
-void
+static void
 intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *connector)
 {
 	struct intel_connector *intel_connector = to_intel_connector(connector);