staging: comedi: adv_pci_dio: restore PCI-1753E support

staging: comedi: adv_pci_dio: restore PCI-1753E support

Back in the old days (before "staging") when Comedi only supported
manual configuration of devices, the "adv_pci_dio" driver supported both
PCI-1753 ("pci1753") and PCI-1753E ("pci1753e").  In actual fact,
"pci1753e" is just a PCI-1753 connected by a ribbon cable to a PCI-1753E
expansion card, which is plugged into a PCI slot but is not a PCI device
itself.  Now that the "adv_pci_dio" driver only supports automatic
configuration of devices and the main "comedi" module no longer allows
auto-configuration to be disabled, a PCI-1753 with a PCI-1753E expansion
card is always treated as an unexpanded PCI-1753 ("pci1753") and there
is no way to override it.  (Recently, an undefined macro
`USE_PCI1753E_BOARDINFO` was used to make the driver switch to
supporting "pci1753e" instead of "pci1753", but this is less than
ideal.)

Advantech has their own Linux (non-Comedi) driver for the PCI-1753 which
detects whether the PCI-1753E expansion card is connected to the
PCI-1753 by fiddling with a register at offset 53 from the main
registers base.

Use Advantech's test in our "adv_pci_dio" driver.  If the board appears
to be a PCI-1753 ("pci1753"), check if the expansion card appears to be
present, and if so, treat the device as a PCI-1753 plus PCI-1753E
expansion card ("pci1753e").

Also, get rid of `enum dio_boardid` (`BOARD_...` enum values) which was
added recently and just use the older `TYPE_...` enum values from `enum
hw_cards_id` instead as the mapping is now 1-to-1.

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