batman-adv: mark existing ogm variables as batman iv

The coming protocol changes also will have a part called "OGM". That
makes it necessary to introduce a distinction in the code base.

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>

diff --cc net/batman-adv/bat_iv_ogm.c
Simple merge

diff --cc net/batman-adv/hard-interface.c
Simple merge

diff --cc net/batman-adv/packet.h
Simple merge