usb: s3c-otg: Rename struct s3c_usbotg_reg to dwc2_usbotg_reg

The driver is actually for the Designware DWC2 controller.
This patch renames struct s3c_usbotg_reg to struct dwc2_usbotg_reg
to make things more obvious and clear.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/gadget/s3c_udc_otg.c b/drivers/usb/gadget/s3c_udc_otg.c
index eb7f77e..00d03f3 100644
--- a/drivers/usb/gadget/s3c_udc_otg.c
+++ b/drivers/usb/gadget/s3c_udc_otg.c
@@ -144,7 +144,7 @@
 /***********************************************************/
 
 void __iomem		*regs_otg;
-struct s3c_usbotg_reg *reg;
+struct dwc2_usbotg_reg *reg;
 
 bool dfu_usb_get_reset(void)
 {
@@ -805,7 +805,7 @@
 
 	dev->pdata = pdata;
 
-	reg = (struct s3c_usbotg_reg *)pdata->regs_otg;
+	reg = (struct dwc2_usbotg_reg *)pdata->regs_otg;
 
 	/* regs_otg = (void *)pdata->regs_otg; */