hw/arm/virt: Clean up local variable shadowing

hw/arm/virt: Clean up local variable shadowing

Fix:

  hw/arm/virt.c:821:22: error: declaration shadows a local variable [-Werror,-Wshadow]
            qemu_irq irq = qdev_get_gpio_in(vms->gic,
                     ^
  hw/arm/virt.c:803:13: note: previous declaration is here
        int irq;
            ^

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-ID: <20230904161235.84651-9-philmd@linaro.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>