staging: unisys: fix CamelCase in destroy_bus()

Fix the CamelCase local variable:

busNo => bus_no

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