config: enable SELinux support

Based on:
https://github.com/CyanogenMod/android_kernel_htc_m7/commit/25d1ca8b2b4a49c1a0f0d13b9c1d0fd8809f9a78
Merge branch 'cm-10.1-wip' of git://github.com/Mustaavalkosta/htc7x30-3.0 into rs-dev