staging: comedi: cb_pcidas64: use pci_ioremap_bar()

Use pci_ioremap_bar() to ioremap the PCI resources. That function
just takes the pci device and a bar number. It also has some
additional sanity checks to make sure the bar is actually a
memory resource.

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>