tests/acpi: list added acpi table binary file for pci bridge hotplug test

The file 'tests/data/acpi/pc/DSDT.hpbridge' is a newly added acpi table file
for testing the pci bridge option 'acpi-pci-hotplug-with-bridge-support' under
i440fx. This change documents this fact.

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200918084111.15339-7-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

tests/qtest/bios-tables-test-allowed-diff.h

 /* List of comma-separated changed AML files to ignore */
+"tests/data/acpi/pc/DSDT.hpbridge",