staging: comedi: amplc_pci224: Prefer using the BIT macro

Fix the checkpatch.pl issues by using the BIT macro and defining some
macros for the multi-bit fields.

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>