fuse: fix kunmap in fuse_ioctl_copy_user

Looks like another victim of the confusing kmap() vs kmap_atomic() API
differences.

Reported-by: Todor Gyumyushev <yodor1@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org

fs/fuse/file.c

@@ -1600,7 +1600,7 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
 			kaddr += copy;
 		}
 
-		kunmap(map);
+		kunmap(page);
 	}
 
 	return 0;