greybus: svc: clean up hello error path

While currently safe, it is unnecessary (and confusing) to try to
destroy the watchdog when watchdog creation fails.

Change the corresponding error path to only deregister the svc.

Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220202113347.1288-3-johan@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>