batman-adv: Drop reduntant batadv interface check

If batadv_hardif_enable_interface is called then its called from its
callback ndo_add_slave. It is therefore not necessary to check if it is a
batadv interface.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

net/batman-adv/hard-interface.c

@@ -9,7 +9,6 @@
 
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
-#include <linux/errno.h>
 #include <linux/gfp.h>
 #include <linux/if.h>
 #include <linux/if_arp.h>
@@ -698,14 +697,6 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
 	kref_get(&hard_iface->refcount);
 
 	dev_hold(soft_iface);
-
-	if (!batadv_softif_is_valid(soft_iface)) {
-		pr_err("Can't create batman mesh interface %s: already exists as regular interface\n",
-		       soft_iface->name);
-		ret = -EINVAL;
-		goto err_dev;
-	}
-
 	hard_iface->soft_iface = soft_iface;
 	bat_priv = netdev_priv(hard_iface->soft_iface);