drm/i915: handle failure path correctly for lvds

In failure path, make sure encoder is cleaned up, otherwise there
is a kernel oops.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_lvds.c

@@ -1149,5 +1149,6 @@ failed:
 	if (intel_output->ddc_bus)
 		intel_i2c_destroy(intel_output->ddc_bus);
 	drm_connector_cleanup(connector);
+	drm_encoder_cleanup(encoder);
 	kfree(intel_output);
 }