staging: comedi: amplc_pci230: remove "legacy" attach mechanism

The "amplc_pci230" driver currently retains the legacy attach mechanism
to allow devices to be attached manually via the `COMEDI_DEVCONFIG`
ioctl.  The only real use for this is to pretend that a PCI230+ or
PCI260+ is a PCI230 or PCI260 for backwards compatibility, as they have
different number of bits of resolution on the AI subdevice.  Since the
card would be automatically configured as a PCI230+ or PCI260+ at PCI
probe time anyway, hopefully any users who want it to appear as a PCI230
or PCI260 would have got tired of removing the automatically configured
device and configuring it manually by now and will have updated their
software to cope with the PCI230+ or PCI260+.

Get rid of the legacy attach mechanism by removing the Comedi driver
"attach" handler `pci230_attach()` and associated code.  Also remove the
"wildcard" entry from the board table `pci230_boards[]` as it is no
longer needed.  Don't bother initializing the `board_name`, `offset`,
and `num_names` members of `struct comedi_driver amplc_pci230_driver`
any longer as they are only needed when configuring the device manually.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>