usb: gadget: Use dbg_ep0() macro instead of serial_printf()

All debug messages from ep0.c except a few are printed by dbg_ep0() macro.
So for remaining few exceptions use also dbg_ep0() instead of serial_printf().

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
diff --git a/drivers/usb/gadget/ep0.c b/drivers/usb/gadget/ep0.c
index 457679f..6624f61 100644
--- a/drivers/usb/gadget/ep0.c
+++ b/drivers/usb/gadget/ep0.c
@@ -294,7 +294,7 @@
 		{
 			struct usb_string_descriptor *string_descriptor;
 			if (!(string_descriptor = usbd_get_string (index))) {
-				serial_printf("Invalid string index %d\n", index);
+				dbg_ep0(0, "Invalid string index %d\n", index);
 				return -1;
 			}
 			dbg_ep0(3, "string_descriptor: %p length %d", string_descriptor, string_descriptor->bLength);
@@ -302,14 +302,14 @@
 		}
 		break;
 	case USB_DESCRIPTOR_TYPE_INTERFACE:
-	serial_printf("USB_DESCRIPTOR_TYPE_INTERFACE - error not implemented\n");
+		dbg_ep0(2, "USB_DESCRIPTOR_TYPE_INTERFACE - error not implemented\n");
 		return -1;
 	case USB_DESCRIPTOR_TYPE_ENDPOINT:
-		serial_printf("USB_DESCRIPTOR_TYPE_ENDPOINT - error not implemented\n");
+		dbg_ep0(2, "USB_DESCRIPTOR_TYPE_ENDPOINT - error not implemented\n");
 		return -1;
 	case USB_DESCRIPTOR_TYPE_HID:
 		{
-			serial_printf("USB_DESCRIPTOR_TYPE_HID - error not implemented\n");
+			dbg_ep0(2, "USB_DESCRIPTOR_TYPE_HID - error not implemented\n");
 			return -1;	/* unsupported at this time */
 #if 0
 			int bNumInterface =
@@ -338,7 +338,7 @@
 		break;
 	case USB_DESCRIPTOR_TYPE_REPORT:
 		{
-			serial_printf("USB_DESCRIPTOR_TYPE_REPORT - error not implemented\n");
+			dbg_ep0(2, "USB_DESCRIPTOR_TYPE_REPORT - error not implemented\n");
 			return -1;	/* unsupported at this time */
 #if 0
 			int bNumInterface =
@@ -531,7 +531,7 @@
 						   le16_to_cpu (request->wValue) & 0xff);
 
 		case USB_REQ_GET_CONFIGURATION:
-			serial_printf("get config %d\n", device->configuration);
+			dbg_ep0(2, "get config %d\n", device->configuration);
 			return ep0_get_one (device, urb,
 					    device->configuration);
 
@@ -621,14 +621,14 @@
 			device->interface = device->alternate = 0;
 
 			/*dbg_ep0(2, "set configuration: %d", device->configuration); */
-			/*serial_printf("DEVICE_CONFIGURED.. event?\n"); */
+			/*dbg_ep0(2, "DEVICE_CONFIGURED.. event?\n"); */
 			return 0;
 
 		case USB_REQ_SET_INTERFACE:
 			device->interface = le16_to_cpu (request->wIndex);
 			device->alternate = le16_to_cpu (request->wValue);
 			/*dbg_ep0(2, "set interface: %d alternate: %d", device->interface, device->alternate); */
-			serial_printf("DEVICE_SET_INTERFACE.. event?\n");
+			dbg_ep0(2, "DEVICE_SET_INTERFACE.. event?\n");
 			return 0;
 
 		case USB_REQ_GET_STATUS: