batman-adv: include gfp.h for GFP_* defines

The linux/gfp.h provides the GFP_ATOMIC and GFP_KERNEL define. It should
therefore be included instead of linux/fs.h.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
diff --git a/net/batman-adv/hash.c b/net/batman-adv/hash.c
index a6dbaf2..2ce0d56 100644
--- a/net/batman-adv/hash.c
+++ b/net/batman-adv/hash.c
@@ -19,7 +19,7 @@
 #include "hash.h"
 #include "main.h"
 
-#include <linux/fs.h>
+#include <linux/gfp.h>
 #include <linux/lockdep.h>
 #include <linux/slab.h>