staging: unisys: fix visorbus Kconfig

Removing visorutil made it impossible to build visorbus. Remove the config
setting from the Kconfig so the module can be enabled in the build.

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