In netkqfilter(), return EINVAL instead of 1 (EPERM) when a filter type

is requested on a network interface file descriptor that is non-applicable.

MFC after:	3 days

sys/net/if.c

@@ -217,7 +217,7 @@ netkqfilter(struct cdev *dev, struct knote *kn)
 		kn->kn_fop = &netdev_filtops;
 		break;
 	default:
-		return (1);
+		return (EINVAL);
 	}
 
 	idx = minor(dev);