net/irda: sh_sir: tidyup compile warning

This patch tidyup below warning

${LINUX}/drivers/net/irda/sh_sir.c:514:6: warning:
 'val' may be used uninitialized in this function
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/irda/sh_sir.c

@@ -513,7 +513,7 @@ static void sh_sir_tx(struct sh_sir_self *self, int phase)
 
 static int sh_sir_read_data(struct sh_sir_self *self)
 {
-	u16 val;
+	u16 val = 0;
 	int timeout = 1024;
 
 	while (timeout--) {