s390/net: fix format string mismatches

cppcheck blamed some issues in drivers/s390/net/...
They are fixed here.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Reported-by: Toralf Foerster <toralf.foerster@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/net/ctcm_sysfs.c b/drivers/s390/net/ctcm_sysfs.c
index 985b5dc..6bcfbbb 100644
--- a/drivers/s390/net/ctcm_sysfs.c
+++ b/drivers/s390/net/ctcm_sysfs.c
@@ -34,8 +34,9 @@
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct net_device *ndev;
-	int bs1;
+	unsigned int bs1;
 	struct ctcm_priv *priv = dev_get_drvdata(dev);
+	int rc;
 
 	ndev = priv->channel[CTCM_READ]->netdev;
 	if (!(priv && priv->channel[CTCM_READ] && ndev)) {
@@ -43,7 +44,9 @@
 		return -ENODEV;
 	}
 
-	sscanf(buf, "%u", &bs1);
+	rc = sscanf(buf, "%u", &bs1);
+	if (rc != 1)
+		goto einval;
 	if (bs1 > CTCM_BUFSIZE_LIMIT)
 					goto einval;
 	if (bs1 < (576 + LL_HEADER_LENGTH + 2))
@@ -143,13 +146,14 @@
 static ssize_t ctcm_proto_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
-	int value;
+	int value, rc;
 	struct ctcm_priv *priv = dev_get_drvdata(dev);
 
 	if (!priv)
 		return -ENODEV;
-	sscanf(buf, "%u", &value);
-	if (!((value == CTCM_PROTO_S390)  ||
+	rc = sscanf(buf, "%d", &value);
+	if ((rc != 1) ||
+	    !((value == CTCM_PROTO_S390)  ||
 	      (value == CTCM_PROTO_LINUX) ||
 	      (value == CTCM_PROTO_MPC) ||
 	      (value == CTCM_PROTO_OS390)))