Revert "Disable KSM"

This reverts commit ab78e2f8b368130d34184ac43ddc03e7aeb1ef79.
Disable CONFIG_OABI_COMPAT
Enable CONFIG_TINY_PREEMPT_RCU
s5pv210: Fix section mismatch warning
s5pv210: rfkill: Fix section mismatch warning
s5pvXXX: cpufreq: Fix 2 section mismatch warnings