staging: unisys: visorbus: convert VMCALL_CONTROLVM_ADDR enum to #define

VMCALL_CONTROLVM_ADDR is the only element left in enum
vmcall_monitor_interface_method_tuple. Converting it to a #define.

Signed-off-by: Sameer Wadgaonkar <sameer.wadgaonkar@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: David Binder <david.binder@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>