staging: comedi: adl_pci6208: remove some useless comments

Remove a number of useless comments that are cut-and-paste from
the skel driver.

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>