drm/i915: Nuke intel_ddi_get_encoder_port()

encoder->port works for FDI, and it also works for MST (regardless of
whether we're dealing with the "fake" MST encoder, or mst->primary).
So let's eliminate intel_ddi_get_encoder_port().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171027193128.14483-4-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_opregion.c

@@ -367,7 +367,7 @@ int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
 	if (intel_encoder->type == INTEL_OUTPUT_DSI)
 		port = 0;
 	else
-		port = intel_ddi_get_encoder_port(intel_encoder);
+		port = intel_encoder->port;
 
 	if (port == PORT_E)  {
 		port = 0;