staging: greybus: arche: remove timesync remains

Remove the remaining timesync bits that were left in the arche platform
driver and which prevented the driver from being compiled.

Fixes: bdfb95c4 ("staging: greybus: remove timesync protocol support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>