staging: unisys: visorbus: controlvm_respond_chipset_init add error handling

Now that visorchannel_signalinsert returns a Linux error code, we need
to convert controlvm_respond_chipset_init to return an error instead of
a void.

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