Menuconfig will not treat 'select FOO' as a real dependency

thus if BAR depends on FOO and FOO depends on other config
options, these dependencies will not be checked.
To fix this, we simply emit all of FOO's depends (only real
dependencies, no select) for BAR as well.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@6293 3c298f89-4303-0410-b956-a3cf2f4a3e73