batman-adv: Provide TTVN in the mesh_info netlink msg

The TTVN is the main information for the debugging of translation table
problems. It is therefore necessary when comparing the global translation
tables.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>