staging: comedi: amplc_pc236: separately configure ISA and PCI

The amplc_pc236 driver supports both ISA and PCI cards, but currently
it is only possible to select the driver if PCI is configured.  This
patch splits the configuration to make the ISA and PCI parts seperately
selectable, and changes the driver to only include the selected ISA
and/or PCI board types.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>