[Bluetooth] Make more functions static

This patch makes another bunch of functions static.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 2104586..e42d728 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -171,4 +171,10 @@
 
 int bt_err(__u16 code);
 
+extern int hci_sock_init(void);
+extern int hci_sock_cleanup(void);
+
+extern int bt_sysfs_init(void);
+extern void bt_sysfs_cleanup(void);
+
 #endif /* __BLUETOOTH_H */