Fixing ntpd time syncing problem

Add ntp.conf file to make ntpd syncing.
Starting ntpd daemon with -g to sync time also with big offsets.
Removes the use of deprecated ntpdate command for initial time sync.

[Peter: drop unused NTPDATE_BIN variable]
Signed-off-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Tested-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>