staging: unisys: visorbus: add error handling to chipset_bus_create

The function chipset_bus_create should return an error. If an error
is returned, it is assumed the response has not been sent by bus_create.

Correctly handle when the error has been returned in visorchipset.

Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: Reviewed-by: Tim Sell <timothy.sell@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>