usb: gadget: udc: net2280: fix sparse error

No functional changes, just fixing one easy
to spot sparse error.

Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc/net2280.c

@@ -2159,7 +2159,7 @@ static void usb_reinit_338x(struct net2280 *dev)
 		if (dev->enhanced_mode) {
 			ep->cfg = &dev->epregs[ne[i]];
 			ep->regs = (struct net2280_ep_regs __iomem *)
-				(((void *)&dev->epregs[ne[i]]) +
+				(((void __iomem *)&dev->epregs[ne[i]]) +
 				ep_reg_addr[i]);
 			ep->fiforegs = &dev->fiforegs[i];
 		} else {