staging: unisys: remove unused CONTROLVM_CHIPSET_SHUTDOWN

this patch removes unused chipset command on the guest
CONTROLVM_CHIPSET_SHUTDOWN

Signed-off-by: Erik Arfvidson <erik.arfvidson@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>