staging: comedi: cb_pcimdda: cleanup pci probe

Make cb_pcimdda_probe() return the pointer to the found pci_dev
and move the comedi_pci_enable() call into the 'attach' function.

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