staging: comedi: das08: Move I/O resource (de)allocation.

Don't deal with allocation and deallocation of I/O resources and PCI
enabling/disabling in the exported functions das08_common_attach() and
das08_common_detach().  Do it in das08_attach() and new function
das08_detach() (which is now the comedi detach() hook for this driver).

This keeps things more symmetrical.  Callers of das08_common_attach()
and das08_common_detach() are now responsible for allocation of their
own I/O resources and enabling of their own devices.  The only external
caller of das08_common_attach() and das08_common_detach() is the
das08_cs module, which looks after its own I/O resources.

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