usb: gadget: f_uac2: restructure some code in afunc_set_alt()

Restructure some code to make it easier to read.

While at it, return -ENOMEM instead of -EINVAL if
usb_ep_alloc_request() fails, and omit the logging in such cases
(the mm core will complain loud enough).
Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_uac2.c

@@ -1104,19 +1104,10 @@ afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
 	usb_ep_enable(ep);
 
 	for (i = 0; i < USB_XFERS; i++) {
-		if (prm->ureq[i].req) {
-			if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
-				dev_err(&uac2->pdev.dev, "%d Error!\n",
-					__LINE__);
-			continue;
-		}
-
+		if (!prm->ureq[i].req) {
 			req = usb_ep_alloc_request(ep, GFP_ATOMIC);
-		if (req == NULL) {
-			dev_err(&uac2->pdev.dev,
-				"%s:%d Error!\n", __func__, __LINE__);
-			return -EINVAL;
-		}
+			if (req == NULL)
+				return -ENOMEM;
 
 			prm->ureq[i].req = req;
 			prm->ureq[i].pp = prm;
@@ -1126,9 +1117,11 @@ afunc_set_alt(struct usb_function *fn, unsigned intf, unsigned alt)
 			req->length = prm->max_psize;
 			req->complete = agdev_iso_complete;
 			req->buf = prm->rbuf + i * req->length;
+		}
 
-		if (usb_ep_queue(ep, req, GFP_ATOMIC))
-			dev_err(&uac2->pdev.dev, "%d Error!\n", __LINE__);
+		if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
+			dev_err(&uac2->pdev.dev, "%s:%d Error!\n",
+				__func__, __LINE__);
 	}
 
 	return 0;