drivers: staging: comedi: fix function prototypes

Add names of parameters to function prototypes in comedi PCI.
Checkpatch reports now no errors.

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