usb: dwc3-of-simple: Add support for RK3399

Add compatible string for RK3399 and enable it by default on
Rockchip platforms with USB3 support.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/usb/host/dwc3-of-simple.c b/drivers/usb/host/dwc3-of-simple.c
index b118997..45df614 100644
--- a/drivers/usb/host/dwc3-of-simple.c
+++ b/drivers/usb/host/dwc3-of-simple.c
@@ -92,6 +92,7 @@
 
 static const struct udevice_id dwc3_of_simple_ids[] = {
 	{ .compatible = "amlogic,meson-gxl-dwc3" },
+	{ .compatible = "rockchip,rk3399-dwc3" },
 	{ .compatible = "ti,dwc3" },
 	{ }
 };