staging: comedi: comedi_fops: rename comedi_set_subdevice_runflags()

`comedi_set_subdevice_runflags()` changes the comedi subdevice's
`runflags` member according to a bit-mask and new bit values.  It's name
might suggest that it only "sets", not "clears".  Rename it to
`comedi_update_subdevice_runflags()` to avoid confusion.

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>