usb: Add MediaTek USB3 DRD driver

This patch adds support for the MediaTek USB3 controller
integrated into MT8173. It currently supports High-Speed
Peripheral Only mode.

Super-Speed Peripheral, Dual-Role Device and Host Only (xHCI)
modes will be added in the next patchs.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 644e978..fbe493d 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -95,6 +95,8 @@
 
 endif
 
+source "drivers/usb/mtu3/Kconfig"
+
 source "drivers/usb/musb/Kconfig"
 
 source "drivers/usb/dwc3/Kconfig"