staging: comedi: ni_660x: move module init code to EOF

Move the module init code to the end of the file. This removes
the need for all the forward declarations.
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>