drm/i915: add HAS_DP_MST feature test macro

Be in line with other features that we have.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -2448,6 +2448,9 @@ struct drm_i915_cmd_table {
 
 #define HAS_IPS(dev)		(IS_HSW_ULT(dev) || IS_BROADWELL(dev))
 
+#define HAS_DP_MST(dev)		(IS_HASWELL(dev) || IS_BROADWELL(dev) || \
+				 INTEL_INFO(dev)->gen >= 9)
+
 #define HAS_DDI(dev)		(INTEL_INFO(dev)->has_ddi)
 #define HAS_FPGA_DBG_UNCLAIMED(dev)	(INTEL_INFO(dev)->has_fpga_dbg)
 #define HAS_PSR(dev)		(IS_HASWELL(dev) || IS_BROADWELL(dev) || \

drivers/gpu/drm/i915/intel_dp.c

@@ -5817,12 +5817,10 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 	intel_dp_aux_init(intel_dp, intel_connector);
 
 	/* init MST on ports that can support it */
-	if (IS_HASWELL(dev) || IS_BROADWELL(dev) || INTEL_INFO(dev)->gen >= 9) {
-		if (port == PORT_B || port == PORT_C || port == PORT_D) {
-			intel_dp_mst_encoder_init(intel_dig_port,
-						  intel_connector->base.base.id);
-		}
-	}
+	if (HAS_DP_MST(dev) &&
+	    (port == PORT_B || port == PORT_C || port == PORT_D))
+		intel_dp_mst_encoder_init(intel_dig_port,
+					  intel_connector->base.base.id);
 
 	if (!intel_edp_init_connector(intel_dp, intel_connector)) {
 		drm_dp_aux_unregister(&intel_dp->aux);