staging: unisys: fix Camelcase in initialize_controlvm_payload()

Fix the CamelCase local variables:

payloadOffset => payload_offset
payloadBytes => payload_bytes

Update all references to use the new names.

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