staging: unisys: fix typedef for VMCALL_MONITOR_INTERFACE_METHOD_TUPLE

Get rid of the typedef for VMCALL_MONITOR_INTERFACE_METHOD_TUPLE in
favor of enum vmcall_monitor_interface_method_tuple.

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