staging: unisys: visorbus: Get rid of passthrough function visorchipset_device_create

The function visorchipset_device_create just called create_visor_device,
we can just combine it with create_visor_device.

Signed-off-by: Sameer Wadgaonkar <sameer.wadgaonkar@unisys.com>
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>