target/s390x: set has_deprecated_props flag

target/s390x: set has_deprecated_props flag

Now that the deprecated_props is an optional field, the expansion method
must now set the "has_deprecated_props" flag in order for the data to be
output from the response.

Fixes: 448553bb7c (qapi: Make CpuModelExpansionInfo::deprecated-props optional and generic)
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250630024404.940882-1-walling@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>