base-files: remove unnecessary early sysctl-hack

git-svn-id: svn://svn.openwrt.org/openwrt@36920 3c298f89-4303-0410-b956-a3cf2f4a3e73
AA: base-files: backport r36920

git-svn-id: svn://svn.openwrt.org/openwrt@36921 3c298f89-4303-0410-b956-a3cf2f4a3e73