staging: comedi: add CMDF_WAKE_EOS as synonym for TRIG_WAKE_EOS

`TRIG_WAKE_EOS` is one of the values that can be OR-ed into the `flags`
member of `struct comedi_cmd`.  It's intended action is tune the
asynchronous command to interrupt at the end of every "scan".  The name
is a bit of a left-over from earlier times.  A better name would be
`CMDF_WAKE_EOS` to match various other command flags.

Define `CMDF_WAKE_EOS` with the same numeric value as the old
`TRIG_WAKE_EOS` and redefine `TRIG_WAKE_EOS` as a synonym of it.

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>