staging: comedi: s626: Kernel doc format comments

Checkpatch emits WARNING: Block comments use a trailing */ on a
separate line. Offending comments are commenting variables within
the main data structure of s626 driver. We can move these comments
to kernel doc format with the benefit of clearing the warning and
improving the documentation for the driver.

Remove comments on structure members. Add original comments to the
head of the structure definition in kernel doc format.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>