hw/arm/virt: fix limit of 64-bit ACPI/ECAM PCI MMIO range

Set the MMIO range limit field to 'base + size - 1' as required.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Shannon Zhao <shannon.zhao@linaro.org>
Message-id: 1463856217-17969-1-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
