usb: gadget: amd5536udc: unconditionally use GFP_ATOMIC in udc_queue()

As far as prep_dma() is called with spinlock held,
we have to pass GFP_ATOMIC regardless of gfp argument.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/amd5536udc.c

@@ -1122,7 +1122,7 @@ udc_queue(struct usb_ep *usbep, struct usb_request *usbreq, gfp_t gfp)
 			goto finished;
 		}
 		if (ep->dma) {
-			retval = prep_dma(ep, req, gfp);
+			retval = prep_dma(ep, req, GFP_ATOMIC);
 			if (retval != 0)
 				goto finished;
 			/* write desc pointer to enable DMA */
@@ -1190,7 +1190,7 @@ udc_queue(struct usb_ep *usbep, struct usb_request *usbreq, gfp_t gfp)
 		 * for PPB modes, because of chain creation reasons
 		 */
 		if (ep->in) {
-			retval = prep_dma(ep, req, gfp);
+			retval = prep_dma(ep, req, GFP_ATOMIC);
 			if (retval != 0)
 				goto finished;
 		}