smdk4412-common: use new SAMSUNG_DVFS flag

Change-Id: I28688bc6419d5ee10cd888a5cb1a3dce038f2e7c
(cherry picked from commit d6eaa964e776d5a6a7693d9962813555baec4517)
BoardCommonConfig: Add LEGACY_EGL and prop edit

Change-Id: I13625579cf3c56303f4eea9ed376f6e0a78126ca
(cherry picked from commit d619e51bd392c6b46343e13913056b3fa5145966)