staging: comedi: refactor jr3_pci driver to remove forward declarations

Move the struct comedi_driver and associated variables to the
end of the source. This is more typical of how other drivers are
written and removes the need for the forward declarations.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>