NTPD in busybox has option -I to bind server to IFACE.
However, capabilities of the busybox are limited, the -I option cannot be
repeated and only one interface can be effectively specified in it.
This option is currently not configurable via UCI.
The patch adds an interface option to the system config, ntp section.
Also sort options for uci_load_validate alphabetically.
Signed-off-by: Alexey Dobrovolsky <dobrovolskiy.alexey@gmail.com>
e12fcf0fe5