Staging: batman-adv: Use kernel version min macro

The kernel headers already provide different versions of a min/max macro
which should be used by all modules according to
Documentation/CodingStyle.
Signed-off-by: Sven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/batman-adv/hard-interface.c

@@ -31,8 +31,6 @@
 
 #include <linux/if_arp.h>
 
-#define MIN(x, y) ((x) < (y) ? (x) : (y))
-
 /* protect update critical side of if_list - but not the content */
 static DEFINE_SPINLOCK(if_list_lock);
 
@@ -220,7 +218,7 @@ int hardif_min_mtu(struct net_device *soft_iface)
 		if (batman_if->soft_iface != soft_iface)
 			continue;
 
-		min_mtu = MIN(batman_if->net_dev->mtu - BAT_HEADER_LEN,
+		min_mtu = min_t(int, batman_if->net_dev->mtu - BAT_HEADER_LEN,
 				min_mtu);
 	}
 	rcu_read_unlock();