staging: comedi: addi_apci_3200: merge addi_apci_3300 support

The addi_apci_3200 and addi_apci_3300 board share the same low-level
hardware code. Merge the drivers.

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