usb: mtu3: register a USB Role Switch for dual role mode

Because extcon is not allowed for new bindings, and the
dual role switch is supported by USB Role Switch,
especially for Type-C drivers, so register a USB Role
Switch to support the new way

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1567070558-29417-12-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/mtu3/mtu3.h

@@ -199,6 +199,9 @@ struct mtu3_gpd_ring {
 * @id_nb : notifier for iddig(idpin) detection
 * @id_work : work of iddig detection notifier
 * @id_event : event of iddig detecion notifier
+* @role_sw : use USB Role Switch to support dual-role switch, can't use
+*		extcon at the same time, and extcon is deprecated.
+* @role_sw_used : true when the USB Role Switch is used.
 * @is_u3_drd: whether port0 supports usb3.0 dual-role device or not
 * @manual_drd_enabled: it's true when supports dual-role device by debugfs
 *		to switch host/device modes depending on user input.
@@ -212,6 +215,8 @@ struct otg_switch_mtk {
 	struct notifier_block id_nb;
 	struct work_struct id_work;
 	unsigned long id_event;
+	struct usb_role_switch *role_sw;
+	bool role_sw_used;
 	bool is_u3_drd;
 	bool manual_drd_enabled;
 };