After issuing a soft reset on the RT8366{S,RB}
switch, waiting for the last acknowlegement fails
in rtl8366_smi_write_reg. Add a _noack version of
the function and use that for issuing a soft reset.
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29844 3c298f89-4303-0410-b956-a3cf2f4a3e73