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>

net/batman-adv/log.h

@@ -9,6 +9,7 @@
 
 #include "main.h"
 
+#include <linux/atomic.h>
 #include <linux/bitops.h>
 #include <linux/compiler.h>
 #include <linux/printk.h>

net/batman-adv/main.h

@@ -205,6 +205,7 @@ enum batadv_uev_type {
 
 /* Kernel headers */
 
+#include <linux/atomic.h>
 #include <linux/compiler.h>
 #include <linux/etherdevice.h>
 #include <linux/if_vlan.h>