staging: comedi: pcl818: clarify pcl818_reset()

Like done in the pcl812 driver, use the boardinfo to determine what
should be reset.

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>