[S390] qdio: prevent compile warning

Prevent the following compile warning for !CONFIG_64BIT:

  CC      drivers/s390/cio/qdio_main.o
drivers/s390/cio/qdio_main.c: In function ‘handle_outbound’:
drivers/s390/cio/qdio_main.c:1449: warning: ‘state’ may be used uninitialized in this function
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/qdio_main.c

@@ -1446,7 +1446,7 @@ static int handle_inbound(struct qdio_q *q, unsigned int callflags,
 static int handle_outbound(struct qdio_q *q, unsigned int callflags,
 			   int bufnr, int count)
 {
-	unsigned char state;
+	unsigned char state = 0;
 	int used, rc = 0;
 
 	qperf_inc(q, outbound_call);