Define the architecture for compressed dump format

Signed-off-by: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>