selinux: drop return at end of void function avc_insert()

Commit 539813e4 ("selinux: stop returning node from avc_insert()")
converted the return value of avc_insert() to void but left the now
unnecessary trailing return statement.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/avc.c

@@ -642,7 +642,6 @@ static void avc_insert(u32 ssid, u32 tsid, u16 tclass,
 	hlist_add_head_rcu(&node->list, head);
 found:
 	spin_unlock_irqrestore(lock, flag);
-	return;
 }
 
 /**