staging: comedi: addi_apci_1564: detect PLD revision for I/O mapping

staging: comedi: addi_apci_1564: detect PLD revision for I/O mapping

The APCI-1564 has different I/O mapping depending on if the PLD revision is
Rev 1.0 or Rev 2.x. The revision can be determined by reading the EEPROM
register at offset 0x00 of PCI BAR 0 and checking the value of bits 7 to 4.

Add this check to apci1564_auto_attach(). Currently this driver is coded
to work with the Rev 2.x I/O mapping. For now, fail the attach if a Rev 1.0
PLD is detected. Document the I/O mapping for both revisions.

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