hw/acpi/pcihp: Clean up global variable shadowing in acpi_pcihp_init()

Fix:

  hw/acpi/pcihp.c:499:36: error: declaration shadows a variable in the global scope [-Werror,-Wshadow]
                       MemoryRegion *address_space_io,
                                     ^
  include/exec/address-spaces.h:35:21: note: previous declaration is here
  extern AddressSpace address_space_io;
                      ^

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20231010115048.11856-5-philmd@linaro.org>

hw/acpi/pcihp.c

@@ -496,8 +496,7 @@ static const MemoryRegionOps acpi_pcihp_io_ops = {
 };
 
 void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
-                     MemoryRegion *address_space_io,
-                     uint16_t io_base)
+                     MemoryRegion *io, uint16_t io_base)
 {
     s->io_len = ACPI_PCIHP_SIZE;
     s->io_base = io_base;
@@ -506,7 +505,7 @@ void acpi_pcihp_init(Object *owner, AcpiPciHpState *s, PCIBus *root_bus,
 
     memory_region_init_io(&s->io, owner, &acpi_pcihp_io_ops, s,
                           "acpi-pci-hotplug", s->io_len);
-    memory_region_add_subregion(address_space_io, s->io_base, &s->io);
+    memory_region_add_subregion(io, s->io_base, &s->io);
 
     object_property_add_uint16_ptr(owner, ACPI_PCIHP_IO_BASE_PROP, &s->io_base,
                                    OBJ_PROP_FLAG_READ);

include/hw/acpi/pcihp.h

@@ -56,7 +56,7 @@ typedef struct AcpiPciHpState {
 } AcpiPciHpState;
 
 void acpi_pcihp_init(Object *owner, AcpiPciHpState *, PCIBus *root,
-                     MemoryRegion *address_space_io, uint16_t io_base);
+                     MemoryRegion *io, uint16_t io_base);
 
 bool acpi_pcihp_is_hotpluggbale_bus(AcpiPciHpState *s, BusState *bus);
 void acpi_pcihp_device_pre_plug_cb(HotplugHandler *hotplug_dev,