net/irda: sh_sir: fixup err return value on sh_sir_open

On sh_sir_open function, there was a possibility that
err variable didn't have value even though it is return value.
This patch modify it.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/irda/sh_sir.c

@@ -645,8 +645,10 @@ static int sh_sir_open(struct net_device *ndev)
 	sh_sir_set_baudrate(self, 9600);
 
 	self->irlap = irlap_open(ndev, &self->qos, DRIVER_NAME);
-	if (!self->irlap)
+	if (!self->irlap) {
+		err = -ENODEV;
 		goto open_err;
+	}
 
 	/*
 	 * Now enable the interrupt then start the queue