batman-adv: Unify include guards style

All other include guards in batman-adv use the style:

* _NET_BATMAN_ADV_$(FILENAME)_
* uppercase only
* "." & "-" replaced with "_"

Use this also in the B.A.T.M.A.N. IV/V OGM implementation headers.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>