staging: comedi: ni_tiocmd: make ni_tio_cmd() a proper comedi (*do_cmd)

Change the parameters to ni_tio_cmd() to make it a proper comedi
(*do_cmd) function.

The wrappers in the ni_660x and ni_mio_common modules are still needed
to request the mite channel and setup the device before actually doing
the command.

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>