[media] vivid-vid-out: use memdup_user()

Instead of allocating and coping from __user, do it using
one atomic call. That makes the code simpler.

Found by coccinelle.
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/platform/vivid/vivid-vid-out.c

@@ -897,14 +897,10 @@ int vidioc_s_fmt_vid_out_overlay(struct file *file, void *priv,
 		return ret;
 
 	if (win->bitmap) {
-		new_bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+		new_bitmap = memdup_user(win->bitmap, bitmap_size);
 
-		if (new_bitmap == NULL)
-			return -ENOMEM;
-		if (copy_from_user(new_bitmap, win->bitmap, bitmap_size)) {
-			kfree(new_bitmap);
-			return -EFAULT;
-		}
+		if (IS_ERR(new_bitmap))
+			return PTR_ERR(new_bitmap);
 	}
 
 	dev->overlay_out_top = win->w.top;