hw/arm/virt-acpi-build: Don't create ITS id mappings by default

hw/arm/virt-acpi-build: Don't create ITS id mappings by default

Commit d6afe18b7242 ("hw/arm/virt-acpi-build: Fix ACPI IORT and MADT tables
when its=off") moved ITS group node generation under the its=on condition.
However, it still creates rc_its_idmaps unconditionally, which results in
duplicate ID mappings in the IORT table.

Fixes:d6afe18b7242 ("hw/arm/virt-acpi-build: Fix ACPI IORT and MADT tables when its=off")
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Donald Dutile <ddutile@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>