kernel: add some config options

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38660 3c298f89-4303-0410-b956-a3cf2f4a3e73
sunxi: drop CONFIG_DEVTMPFS option

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38661 3c298f89-4303-0410-b956-a3cf2f4a3e73