Revert "Kbuild: Export additional Exynos headers"

This reverts commit cfbd1494e0323d9a006138e31056f957a37ab47b.
Revert "performance: Turn CPUs online while active"

This reverts commit c7480e2552e8b64bf677f776c3a430c98d606456.
Revert "clock-exynos4212: populate vpll_date with more frequencies"

This reverts commit 311cd72390037c548d9b97a3091605476b2b9724.