staging: comedi: ni_6527: remove #include "comedi_fc.h"

staging: comedi: ni_6527: remove #include "comedi_fc.h"

As preparation for removal of "comedi_fc.h", replace calls to the
`cfc_check_trigger_...` functions from "comedi_fc.h" with the
replacement `comedi_check_trigger_...` functions from "../comedidev.h"
and remove the inclusion of "comedi_fc.h".

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>