6rd: Make don't fragment bit (df) a configurable variable

Make the IPv4 "do not fragment" bit a configurable variable for the 6rd
tunnel interface as the bit should not be set in the encapsulating IPv4
header according to RFC3056.
On top the config variable allows to enable/disable path mtu discovery
for tunnel interfaces.
Config variable can be passed to netifd as tunnel config support is
already present for the "do not fragment" bit.

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39370 3c298f89-4303-0410-b956-a3cf2f4a3e73
odhcpd: fix certain config values being overwritten

Thanks to Hans Dedecker for the fix.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39371 3c298f89-4303-0410-b956-a3cf2f4a3e73
[package] base-files: add ucidef_add_switch_port function

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39372 3c298f89-4303-0410-b956-a3cf2f4a3e73
ar71xx: create wndr3700 network config from uci-defaults

Since that was the last configuration in defconfig directory we can drop the
defconfig init script too.

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39373 3c298f89-4303-0410-b956-a3cf2f4a3e73