Move acpi_build_srat_memory to common place so that it could be reused
by ARM. Rename it to build_srat_memory.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: NShannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Message-id: 1461667229-9216-5-git-send-email-zhaoshenglong@huawei.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>