batman-adv: include kobject.h for kobject_* functions

The linux/kobject.h provides the kobject_* function declarations and should
therefore be included directly before they are used.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/sysfs.c

@@ -27,6 +27,7 @@
 #include <linux/if.h>
 #include <linux/if_vlan.h>
 #include <linux/kernel.h>
+#include <linux/kobject.h>
 #include <linux/kref.h>
 #include <linux/netdevice.h>
 #include <linux/printk.h>