acpi/tests/avocado/bits: add mformat as one of the dependencies

acpi/tests/avocado/bits: add mformat as one of the dependencies

mformat is needed by grub-mkrescue and hence, add this as one of the
dependencies to run bits tests. This avoids errors such as the following:

/var/tmp/acpi-bits-wju6tqoa.tmp/grub-inst-x86_64-efi/bin/grub-mkrescue: 360: mformat: not found

Signed-off-by: Ani Sinha <ani@anisinha.ca>
Message-Id: <20221203132407.34539-1-ani@anisinha.ca>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>