greybus: control: move timesync-operation functions

Move the timesync-operation functions above the control-object
management functions, which is where all other operation implementations
reside.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>