staging: comedi: addi_apci_3120: move APCI3120_FIFO_ADVANCE_ON_BYTE_2

Move this define to the main driver source and convert it to a bit-shift.

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>