ipq806x: refresh kernel configs

Remove options which have been moved into the generic config ever since.

Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46558 3c298f89-4303-0410-b956-a3cf2f4a3e73