staging: unisys: fix CamelCase in struct add_vbus_guestpart

Clean up CamelCase names:
busNo => bus_no
deviceCount => dev_count
busTypeGuid => bus_uuid
busInstGuid => instance_guid

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