hw/acpi/viot: move the individual PCI host bridge entry generation to a new function

hw/acpi/viot: move the individual PCI host bridge entry generation to a new function

Instead of generating each table entry inline, move the individual PCI host bridge
table entry generation to a separate build_pci_host_range() function.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220525173232.31429-3-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>