drm/i915: fix the "ghost eDP" encoder unwind path

Because calling intel_dp_encoder_destroy inside
intel_edp_init_connector is just wrong. This is the initialization
path, so we should properly unwind all the initialization through the
whole caller stack.

On the intel_dp_encoder_destroy function we do the following:
1 - Call i2c_del_adapter
2 - Call drm_encoder_cleanup
3 - If edp:
3.1 - Cancel panel_vdd_work
3.2 - Call ironlake_panel_vdd_of_sync
4 - Free the encoder

And here is how we unwind each specific step:
1 - We have intel_dp_init_connector -> intel_dp_i2c_init ->
    i2c_dp_aux_add_bus -> i2c_add_adapter, so we call
    i2c_del_dapter at intel_dp_init_connector
2 - Call it in the same function that called drm_encoder_init
3 - Call it in the same function that called INIT_DELAYED_WORK
4 - Free it in the same function that allocated it

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Zoltan Nyul <zoltan.nyul@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_ddi.c

@@ -1357,6 +1357,8 @@ void intel_ddi_init(struct drm_device *dev, enum port port)
 	intel_encoder->hot_plug = intel_ddi_hot_plug;
 
 	if (!intel_dp_init_connector(intel_dig_port, dp_connector)) {
+		drm_encoder_cleanup(encoder);
+		kfree(intel_dig_port);
 		kfree(dp_connector);
 		return;
 	}

drivers/gpu/drm/i915/intel_dp.c

@@ -2986,7 +2986,6 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	} else {
 		/* if this fails, presume the device is a ghost */
 		DRM_INFO("failed to retrieve link info, disabling eDP\n");
-		intel_dp_encoder_destroy(&intel_dig_port->base.base);
 		return false;
 	}
 
@@ -3146,6 +3145,13 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 	intel_dp_i2c_init(intel_dp, intel_connector, name);
 
 	if (!intel_edp_init_connector(intel_dp, intel_connector)) {
+		i2c_del_adapter(&intel_dp->adapter);
+		if (is_edp(intel_dp)) {
+			cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
+			mutex_lock(&dev->mode_config.mutex);
+			ironlake_panel_vdd_off_sync(intel_dp);
+			mutex_unlock(&dev->mode_config.mutex);
+		}
 		drm_sysfs_connector_remove(connector);
 		drm_connector_cleanup(connector);
 		return false;
@@ -3208,6 +3214,9 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port)
 	intel_encoder->cloneable = false;
 	intel_encoder->hot_plug = intel_dp_hot_plug;
 
-	if (!intel_dp_init_connector(intel_dig_port, intel_connector))
+	if (!intel_dp_init_connector(intel_dig_port, intel_connector)) {
+		drm_encoder_cleanup(encoder);
+		kfree(intel_dig_port);
 		kfree(intel_connector);
+	}
 }