PCI: ibmphp: Fix use-before-set in get_max_bus_speed()

The "rc" variable is only initialized on the error path.  The caller
doesn't check the return but, if "rc" is non-zero, then this function is
basically a no-op.

Fixes: 3749c51a ("PCI: Make current and maximum bus speeds part of the PCI core")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

drivers/pci/hotplug/ibmphp_core.c

@@ -379,7 +379,7 @@ static int get_adapter_present(struct hotplug_slot *hotplug_slot, u8 *value)
 
 static int get_max_bus_speed(struct slot *slot)
 {
-	int rc;
+	int rc = 0;
 	u8 mode = 0;
 	enum pci_bus_speed speed;
 	struct pci_bus *bus = slot->hotplug_slot->pci_slot->bus;