s390/pci: disable per default

Disable pci on s390. Enable with pci=on.

Suggested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 6a054bf..dd8e13e 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -1106,13 +1106,13 @@
 }
 EXPORT_SYMBOL_GPL(zpci_deregister_hp_ops);
 
-unsigned int s390_pci_probe = 1;
+unsigned int s390_pci_probe;
 EXPORT_SYMBOL_GPL(s390_pci_probe);
 
 char * __init pcibios_setup(char *str)
 {
-	if (!strcmp(str, "off")) {
-		s390_pci_probe = 0;
+	if (!strcmp(str, "on")) {
+		s390_pci_probe = 1;
 		return NULL;
 	}
 	return str;