function doesn't need RW aceess to passed in bus pointer,
make it const.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 include/hw/pci/pci.h | 2 +-
 hw/pci/pci.c         | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 7048a373d1..03e8d614ad 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -270,7 +270,7 @@ typedef void (*pci_bus_dev_fn)(PCIBus *b, PCIDevice *d, void *opaque);
 typedef void (*pci_bus_fn)(PCIBus *b, void *opaque);
 typedef void *(*pci_bus_ret_fn)(PCIBus *b, void *opaque);
 
-bool pci_bus_is_express(PCIBus *bus);
+bool pci_bus_is_express(const PCIBus *bus);
 
 void pci_root_bus_init(PCIBus *bus, size_t bus_size, DeviceState *parent,
                        const char *name,
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index c2fb88f9a3..e725a771e3 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -482,7 +482,7 @@ static void pci_bus_uninit(PCIBus *bus)
     pci_host_bus_unregister(BUS(bus)->parent);
 }
 
-bool pci_bus_is_express(PCIBus *bus)
+bool pci_bus_is_express(const PCIBus *bus)
 {
     return object_dynamic_cast(OBJECT(bus), TYPE_PCIE_BUS);
 }
-- 
2.31.1