netifd: implement IPv6 prefix deprecation according to RFC 6204

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35377 3c298f89-4303-0410-b956-a3cf2f4a3e73
[kernel] fix mtd_mp25p80_add_gd25q32_gd25q64.patch

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@35378 3c298f89-4303-0410-b956-a3cf2f4a3e73