staging: comedi: adl_pci9118: don't reset digital outputs

Currently this driver resets the digital output channels to a low state
when the driver is attached and detached.

Since the digital output state can be read, initialize the subdevice
state when the driver is attached and don't reset them.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>