staging: comedi: amplc_pc236: split pc236_boards[] into ISA & PCI

Split `pc236_boards[]` into `pc236_isa_boards[]` for ISA cards and
`pc236_pci_boards[]` for PCI cards (there is only one of each).  Only
initialize the board name look-up members of `struct comedi_driver
amplc_pc236_driver` if the ISA part of the driver is enabled in the
kernel config (`CONFIG_COMEDI_AMPLC_PC236_ISA`) using the array of ISA
boards (`pc236_isa_boards[]`).  The driver doesn't allow manual
configuration of PCI devices, so there is no point having the comedi
core match the names of the PCI boards before it calls our driver's
legacy attach routine (`pc236_attach()`).

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>