ramips: fix devicetree corruption with some boot loaders if the cache…

…s are not ready at boot

Signed-off-by: John Crispin <blogic@openwrt.org>

Backport of r46766

git-svn-id: svn://svn.openwrt.org/openwrt/branches/chaos_calmer@46767 3c298f89-4303-0410-b956-a3cf2f4a3e73