[PATCH] drivers/media/video __user annotations and fixes

* compat_alloc_user_space() returns __user pointer
* copying between two userland areas is copy_in_user(), not copy_from_user()
* dereferencing userland pointers is bad
* so's get_user() from local variables

... plus usual __user annotations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index b23be44..5208b12d 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -549,7 +549,7 @@
 struct v4l2_clip
 {
 	struct v4l2_rect        c;
-	struct v4l2_clip	*next;
+	struct v4l2_clip	__user *next;
 };
 
 struct v4l2_window