batman-adv: Remove unused sched.h include

The linux/wait.h include was removed with commit 421d988b2c08 ("batman-adv:
Consolidate logging related functions"). The previously required (but not
unused) linux/sched.h include can also be dropped now.
Signed-off-by: NSven Eckelmann <sven@narfation.org>
Signed-off-by: NSimon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/debugfs.c

@@ -26,7 +26,6 @@
 #include <linux/fs.h>
 #include <linux/netdevice.h>
 #include <linux/printk.h>
-#include <linux/sched.h> /* for linux/wait.h */
 #include <linux/seq_file.h>
 #include <linux/stat.h>
 #include <linux/stddef.h>