usb: misc: usbtest: delete useless memset for urbs array

The element of urbs array will be initialized at below code
at once.

	for (i = 0; i < param->sglen; i++) {
		urbs[i] = iso_alloc_urb(udev, pipe, desc,
					param->length, offset);
Acked-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/misc/usbtest.c

@@ -1920,7 +1920,6 @@ test_iso_queue(struct usbtest_dev *dev, struct usbtest_param *param,
 	init_completion(&context.done);
 	spin_lock_init(&context.lock);
 
-	memset(urbs, 0, sizeof(urbs));
 	udev = testdev_to_usbdev(dev);
 	dev_info(&dev->intf->dev,
 		"iso period %d %sframes, wMaxPacket %d, transactions: %d\n",