ntp: update sample config

Drop redundant IP version and double default restrict.
Tweak KoD and other defaults for properness.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/ntp/ntpd.etc.conf

@@ -1,8 +1,8 @@
 server 0.pool.ntp.org iburst
 server 1.pool.ntp.org iburst
 
-restrict default kod nomodify notrap nopeer noquery
-restrict -6 default kod nomodify notrap nopeer noquery
-
+# Allow only time queries, at a limited rate, sending KoD when in excess.
+# Allow all local queries (IPv4, IPv6)
+restrict default nomodify nopeer noquery limited kod
 restrict 127.0.0.1
-restrict -6 ::1
+restrict [::1]