staging: comedi: ssv_dnp: tidy up multi-line comments

Format the multi-line comments in the kernel CodingStyle.

Move the comment about the I/O ports in dnp_attach() to the start
of the function. This is typically where the resources are reserved.

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>