usb: gadget: uvc: Use GFP_ATOMIC under spin lock

Found using the following semantic patch:
<spml>
@@
@@
spin_lock_irqsave(...);
... when != spin_unlock_irqrestore(...);
* GFP_KERNEL
</spml>

Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Bhupesh Sharma <bhupesh.sharma@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/uvc_video.c

@@ -314,7 +314,8 @@ uvc_video_pump(struct uvc_video *video)
 		video->encode(req, video, buf);
 
 		/* Queue the USB request */
-		if ((ret = usb_ep_queue(video->ep, req, GFP_KERNEL)) < 0) {
+		ret = usb_ep_queue(video->ep, req, GFP_ATOMIC);
+		if (ret < 0) {
 			printk(KERN_INFO "Failed to queue request (%d)\n", ret);
 			usb_ep_set_halt(video->ep);
 			spin_unlock_irqrestore(&video->queue.irqlock, flags);