staging: comedi: addi_apci_3xxx: simplify the PCI bar reading

The boards supported by this driver all have an ADDIDATA_9054 eeprom.
Knowing this we can simplify the code that reads the PCI bars to get
the iobase address used by the driver.

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>