drm/i915/ddi: Move DDI port detection to the corresponding helper

We have already a function to detect DDI ports using VBT, so instead of
opencoding the DDI specific version of this, move the opencoded part to
the existing helper.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181220132604.25222-1-imre.deak@intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_bios.c

@@ -1946,6 +1946,15 @@ bool intel_bios_is_port_present(struct drm_i915_private *dev_priv, enum port por
 	};
 	int i;
 
+	if (HAS_DDI(dev_priv)) {
+		const struct ddi_vbt_port_info *port_info =
+			&dev_priv->vbt.ddi_port_info[port];
+
+		return port_info->supports_dp ||
+		       port_info->supports_dvi ||
+		       port_info->supports_hdmi;
+	}
+
 	/* FIXME maybe deal with port A as well? */
 	if (WARN_ON(port == PORT_A) || port >= ARRAY_SIZE(port_mapping))
 		return false;

drivers/gpu/drm/i915/intel_display.c

@@ -14362,9 +14362,7 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
 		 * On SKL we don't have a way to detect DDI-E so we rely on VBT.
 		 */
 		if (IS_GEN9_BC(dev_priv) &&
-		    (dev_priv->vbt.ddi_port_info[PORT_E].supports_dp ||
-		     dev_priv->vbt.ddi_port_info[PORT_E].supports_dvi ||
-		     dev_priv->vbt.ddi_port_info[PORT_E].supports_hdmi))
+		    intel_bios_is_port_present(dev_priv, PORT_E))
 			intel_ddi_init(dev_priv, PORT_E);
 
 	} else if (HAS_PCH_SPLIT(dev_priv)) {