usb: dwc3: unmap the proper number of sg entries

num_sgs contains the number of sgs assigned by the gadget.
num_mapped_sgs contains the number of mapped sgs which may differ from
the gadget's values. For dma_unmap_sg() we have to provide the value
which was returned by dma_map_sg().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a696bde..064b6e2 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -101,7 +101,7 @@
 	if (req->request.num_mapped_sgs) {
 		req->request.dma = DMA_ADDR_INVALID;
 		dma_unmap_sg(dwc->dev, req->request.sg,
-				req->request.num_sgs,
+				req->request.num_mapped_sgs,
 				req->direction ? DMA_TO_DEVICE
 				: DMA_FROM_DEVICE);