chrony: improve hotplug and init scripts

- fix the init script to read the right config
- rework the init script to allow reusing its code in the hotplug script
- find wan interfaces in the hotplug script instead of using hardcoded
  name and set the online/offline status separately for IPv4/IPv6
- allow NTP access on interfaces that are configured after chronyd start
- add NTP servers obtained from DHCP, options are specified in a new
  dhcp_ntp_server config section
- start chronyd before the network service, include a patch to always
  have IP_FREEBIND defined, which seems to be missing with uclibc

Signed-off-by: Miroslav Lichvar <mlichvar0@gmail.com>

net/chrony/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=chrony
 PKG_VERSION:=2.2
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=http://download.tuxfamily.org/chrony/