usb: dwc3: drd: use helper to get role-switch-default-mode

Use the new helper usb_get_role_switch_default_mode() to
get property of "role-switch-default-mode"
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1626340078-29111-7-git-send-email-chunfeng.yun@mediatek.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/drd.c

@@ -541,14 +541,10 @@ static enum usb_role dwc3_usb_role_switch_get(struct usb_role_switch *sw)
 static int dwc3_setup_role_switch(struct dwc3 *dwc)
 {
 	struct usb_role_switch_desc dwc3_role_switch = {NULL};
-	const char *str;
 	u32 mode;
-	int ret;
 
-	ret = device_property_read_string(dwc->dev, "role-switch-default-mode",
-					  &str);
-	if (ret >= 0  && !strncmp(str, "host", strlen("host"))) {
-		dwc->role_switch_default_mode = USB_DR_MODE_HOST;
+	dwc->role_switch_default_mode = usb_get_role_switch_default_mode(dwc->dev);
+	if (dwc->role_switch_default_mode == USB_DR_MODE_HOST) {
 		mode = DWC3_GCTL_PRTCAP_HOST;
 	} else {
 		dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;