usb: mtu3: add generic compatible string

The mtu3 driver is a generic driver for MediaTek usb3 DRD IP, add
a generic compatible to avoid confusion when support new SoCs but
use a compatible with specific SoC's name "mt8173".

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/mtu3/mtu3_plat.c

@@ -500,6 +500,7 @@ static const struct dev_pm_ops mtu3_pm_ops = {
 
 static const struct of_device_id mtu3_of_match[] = {
 	{.compatible = "mediatek,mt8173-mtu3",},
+	{.compatible = "mediatek,mtu3",},
 	{},
 };