The PR adds the support for s390x.
In the case of CCW devices, the vhost-user devices are not supported.
See #659. An error message is thrown if they tried to be used.
Memory hotplug is not supported on s390 yet and an error message is thrown.
The VirtioNetPCI has been changed to VirtioNet. The generalization
allows to set the VirtioNet to the correct CCW device for s390x.
Fixes: #666
Co-authored-by: Yash D Jain ydjainopensource@gmail.com
Signed-off-by: Alice Frosi <afrosi@de.ibm.com>
