hw/core/machine: diagnose wrapping of maxmem

hw/core/machine: diagnose wrapping of maxmem

The 'maxmem' parameter parsed on the command line is held in uint64_t
and then assigned to the MachineState field that is 'ram_addr_t'. This
assignment will wrap on 32-bit hosts, silently changing the user's
config request if it were over-sized.

Improve the existing diagnositics for validating 'size', and add the
same diagnostics for 'maxmem'

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Ani Sinha <anisinha@redhat.com>
Reviewed-by: Ani Sinha <anisinha@redhat.com>
Message-ID: <20241127114057.255995-1-berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>