xio3130_downstream: typo fix

slt ctl/status are passed in incorrect order.
Fix this up.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>

hw/pci-bridge/xio3130_downstream.c

@@ -43,7 +43,7 @@ static void xio3130_downstream_write_config(PCIDevice *d, uint32_t address,
 {
     uint16_t slt_ctl, slt_sta;
 
-    pcie_cap_slot_get(d, &slt_sta, &slt_ctl);
+    pcie_cap_slot_get(d, &slt_ctl, &slt_sta);
     pci_bridge_write_config(d, address, val, len);
     pcie_cap_flr_write_config(d, address, val, len);
     pcie_cap_slot_write_config(d, slt_ctl, slt_sta, address, val, len);