usb: gadget: goku: use generic map/unmap routines

those routines have everything we need to map/unmap
USB requests and it's better to use them.
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/gadget/goku_udc.c

@@ -311,12 +311,9 @@ done(struct goku_ep *ep, struct goku_request *req, int status)
 		status = req->req.status;
 
 	dev = ep->dev;
-	if (req->mapped) {
-		pci_unmap_single(dev->pdev, req->req.dma, req->req.length,
-			ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
-		req->req.dma = DMA_ADDR_INVALID;
-		req->mapped = 0;
-	}
+
+	if (ep->dma)
+		usb_gadget_unmap_request(&dev->gadget, &req->req, ep->is_in);
 
 #ifndef USB_TRACE
 	if (status && status != -ESHUTDOWN)
@@ -737,10 +734,11 @@ goku_queue(struct usb_ep *_ep, struct usb_request *_req, gfp_t gfp_flags)
 		return -EBUSY;
 
 	/* set up dma mapping in case the caller didn't */
-	if (ep->dma && _req->dma == DMA_ADDR_INVALID) {
-		_req->dma = pci_map_single(dev->pdev, _req->buf, _req->length,
-			ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
-		req->mapped = 1;
+	if (ep->dma) {
+		status = usb_gadget_map_request(&dev->gadget, &req->req,
+				ep->is_in);
+		if (status)
+			return status;
 	}
 
 #ifdef USB_TRACE