s390x/cpumodel: wire up cpu type + id for TCG

Let's properly expose the CPU type (machine-type number) via "STORE CPU
ID" and "STORE SUBSYSTEM INFORMATION".

As TCG emulates basic mode, the CPU identification number has the format
"Annnnn", whereby A is the CPU address, and n are parts of the CPU serial
number (0 for us for now).

A specification exception will be injected if the address is not aligned
to a double word. Low address protection will not be checked as
we're missing some more general support for that.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20170609133426.11447-3-david@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
