staging: unisys: visorbus: remove POSTCODE from create_visor_device

Remove POSTCODES from create_visor_device, when we fail log an error
with dev_err.

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