staging: comedi: adv_pci_dio: move and rename the MAX_*_SUBDEV[SG] defines

For aesthetics, move these defines after the register defines and rename
them to have namespace associated with the driver.

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>