drm/i915: Only ignore eDP ports that are connected

If the VBT says that a certain port should be eDP (and hence fused off
from HDMI), but in reality it isn't, we need to try and acquire the HDMI
connection instead. So only trust the VBT edp setting if we can connect
to an eDP device on that port.

Fixes: d2182a6608 (drm/i915: Don't register HDMI connectors for eDP ports on VLV/CHV)
References: https://bugs.freedesktop.org/show_bug.cgi?id=96288
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Phidias Chiang <phidias.chiang@canonical.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464766070-31623-1-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 096acbf0..7dfff87 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5568,9 +5568,9 @@
 	return false;
 }
 
-void
-intel_dp_init(struct drm_device *dev,
-	      i915_reg_t output_reg, enum port port)
+bool intel_dp_init(struct drm_device *dev,
+		   i915_reg_t output_reg,
+		   enum port port)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_digital_port *intel_dig_port;
@@ -5580,7 +5580,7 @@
 
 	intel_dig_port = kzalloc(sizeof(*intel_dig_port), GFP_KERNEL);
 	if (!intel_dig_port)
-		return;
+		return false;
 
 	intel_connector = intel_connector_alloc();
 	if (!intel_connector)
@@ -5637,7 +5637,7 @@
 	if (!intel_dp_init_connector(intel_dig_port, intel_connector))
 		goto err_init_connector;
 
-	return;
+	return true;
 
 err_init_connector:
 	drm_encoder_cleanup(encoder);
@@ -5645,8 +5645,7 @@
 	kfree(intel_connector);
 err_connector_alloc:
 	kfree(intel_dig_port);
-
-	return;
+	return false;
 }
 
 void intel_dp_mst_suspend(struct drm_device *dev)