staging: unisys: move hypervisor calls into visorbus

Move hypervisor calls into visorbus and move vbusdeviceinfo.h into
visorbus.
Drivers will call into that to update clientInfo field.

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