cpufreq: add voltage control interfaces
(cherry picked from commit cdfaa8a867ce69e339a085051c8732f3731c9278)
(cherry picked from commit b0117c666692461a7ae878a4abd12f3e545304f6)
(cherry picked from commit 2bc251d063beffcba157da66c640ec122ed0edb7)
smdk4412: Notification LED controls

Change-Id: Ic20c4946d4ea2336e1fa844d6600469e3517752d