staging: comedi: amplc_dio200: split into ISA, PCI and common

staging: comedi: amplc_dio200: split into ISA, PCI and common

Split the "amplc_dio200" comedi driver module into separate driver
modules for ISA and PCI boards with a common module for the shared code.

Keep the old name "amplc_dio200" for the ISA board driver as the module
may be modprobed with this name by a script.  (If the script uses insmod
it will need modifying to load the "amplc_dio200_common" module first.)

Use the module name "amplc_dio200_pci" for the PCI board driver.  On
most systems this will be auto-loaded.

Use the module name "amplc_dio200_common" for the module containing the
shared code.  This is normally loaded as a dependency of the other two
modules.

"amplc_dio200_common" exports the following functions:

* `amplc_dio200_common_attach()`: this is basically the old
  `dio200_common_attach()` from the combined driver module.  It is
  called from the driver-specific attach or auto-attach routines.
* `amplc_dio200_common_detach()`: this is most of the old
  `dio200_detach()`.  It is called from the driver-specific detach
  routine.
* `amplc_dio200_set_enhance()`: this is a new function called during
  initialization of PCIe cards to enable "enhanced" mode.

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