staging: comedi: cb_pcidas64: remove the base_address_regions enum

This enum is only used in the ioremap of the PCI resources and it
doesn't really help make the code any clearer.

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>