usb: gadget: udc: gr_udc: fix memleak on error handling path in gr_ep_init()

gr_ep_init() does not assign the allocated request anywhere if allocation
of memory for the buffer fails. This is a memory leak fixed by the given
patch.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Evgeny Novikov <novikov@ispras.ru>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/udc/gr_udc.c

@@ -1980,9 +1980,12 @@ static int gr_ep_init(struct gr_udc *dev, int num, int is_in, u32 maxplimit)
 
 	if (num == 0) {
 		_req = gr_alloc_request(&ep->ep, GFP_ATOMIC);
+		if (!_req)
+			return -ENOMEM;
+
 		buf = devm_kzalloc(dev->dev, PAGE_SIZE, GFP_DMA | GFP_ATOMIC);
-		if (!_req || !buf) {
-			/* possible _req freed by gr_probe via gr_remove */
+		if (!buf) {
+			gr_free_request(&ep->ep, _req);
 			return -ENOMEM;
 		}