s390x/sclp: reporting the maximum nested topology entries

The maximum nested topology entries is used by the guest to
know how many nested topology are available on the machine.

Let change the MNEST value from 2 to 4 in the SCLP READ INFO
structure now that we support books and drawers.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20231016183925.2384704-6-nsg@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2 files changed