usb: typec: altmodes/displayport: Notify drm subsys of hotplug events

Use the new drm_connector_oob_hotplug_event() functions to let drm/kms
drivers know about DisplayPort over Type-C hotplug events.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20210817215201.795062-9-hdegoede@redhat.com