usb: s3c-otg: Rename struct s3c_udc to dwc2_udc

The driver is actually for the Designware DWC2 controller.
This patch renames struct s3c_udc to struct dwc2_udc to make
things more obvious and clear.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/gadget/s3c_udc_otg_phy.c b/drivers/usb/gadget/s3c_udc_otg_phy.c
index 963b617..ffc930c 100644
--- a/drivers/usb/gadget/s3c_udc_otg_phy.c
+++ b/drivers/usb/gadget/s3c_udc_otg_phy.c
@@ -37,7 +37,7 @@
 
 #include <usb/s3c_udc.h>
 
-void otg_phy_init(struct s3c_udc *dev)
+void otg_phy_init(struct dwc2_udc *dev)
 {
 	unsigned int usb_phy_ctrl = dev->pdata->usb_phy_ctrl;
 	struct s3c_usbotg_phy *phy =
@@ -75,7 +75,7 @@
 	udelay(10);
 }
 
-void otg_phy_off(struct s3c_udc *dev)
+void otg_phy_off(struct dwc2_udc *dev)
 {
 	unsigned int usb_phy_ctrl = dev->pdata->usb_phy_ctrl;
 	struct s3c_usbotg_phy *phy =