staging: comedi: cb_pcidas: refactor 'ranges' boardinfo

All the boards, except the 'pci-das1001', use the normal analog input
range table 'cb_pcidas_ranges'. Convert the 'ranges' boardinfo into
a bit-field flag 'use_alt_range' to save a bit of space.

For aesthetics, reword the comments in the boardinfo for the bit-field
members so they align.

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>