Btrfs: initial move to kernel module land

Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/root-tree.c

@@ -1,7 +1,4 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include "kerncompat.h"
-#include "radix-tree.h"
+#include <linux/module.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "print-tree.h"