batman-adv: add debugfs support to view multiif tables

Show tables for the multi interface operation. Originator tables
are added per hard interface.

This patch also changes the API by adding the interface to the
bat_orig_print() parameters.

Signed-off-by: Simon Wunderlich <simon@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>