staging: comedi: addi_apci_3xxx: tidy up the ttl digital i/o subdevice init

For aesthetic reasons, add some whitespace to the initialization of the
ttl digital i/o subdevices.

Fix the subdev_flags for the subdevice. The SDF_GROUND and SDF_COMMON
flags only apply to analog subdevices.

Fix the s->iobits for the subdevice. According to the datasheet:
	Port 0 (channels 0-7) are always outputs
	Port 1 (channels 8-15) are always inputs
	Port 2 (channels 9-23) are programmable i/o (default to inputs)

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>