QEMU's command line visitor as well as the JSON interface take bytes by
default for memory object sizes. Convert mebibytes to bytes so that we
can later refactor the existing code for hotplug purposes.
Currently, we only bind the whole QEMU domain to memory nodes
specified in nodemask altogether. That, however, doesn't make much
sense when one wants to control from where the memory for particular
guest nodes should be allocated. QEMU allows us to do that by
specifying 'host-nodes' parameter for the 'memory-backend-ram' object,
so let's use that.
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>