hw/s390x/ccw: Remove local Error variable from s390_ccw_realize()

hw/s390x/ccw: Remove local Error variable from s390_ccw_realize()

Use the 'Error **errp' argument of s390_ccw_realize() instead and
remove the error_propagate() call.

Signed-off-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240522170107.289532-4-clg@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>