linux-imx

batman-adv: Add missing include for atomic functions

main.h is using atomic_add_unless and log.h atomic_read. The main
header linux/atomic.h should be included for these files.

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