staging: comedi: move COMEDI_SRF_... macros to "comedi_fops.c"

The `COMEDI_SRF_...` macros define flag combinations in the `runflags`
member of `struct comedi_subdevice`.  They are only used directly in
"comedi_fops.c", so move them to there.

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>