"devlink health" was used as a way to monitor the GNSS signal
status.  This isn't really the intended use, and the same
functionality can be achived by monitoring the status file.

Remove the devlink heath support entirely, and also remove the
currently unused devlink parameters.
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>