s390/pci: improve ZPCI_* macros

Most of the constants defined in pci_io.h depend on each other
and thus can be calculated.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.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 3942348..3627ae0 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -541,7 +541,7 @@
 
 static int zpci_alloc_iomap(struct zpci_dev *zdev)
 {
-	int entry;
+	unsigned long entry;
 
 	spin_lock(&zpci_iomap_lock);
 	entry = find_first_zero_bit(zpci_iomap, ZPCI_IOMAP_MAX_ENTRIES);