cpufreq: ElementalX: Move get_cpu_idle_time() to cpufreq.c

Change-Id: I059e0caeaa4a8926aa606144e5b2371d093179f4
cpufreq: ElementalX: fix trace conflicts with interactive

Change-Id: I8bac275b380e5c51be893435feb05caad9787ef8
defconfig: enable ElementalX governor

Change-Id: I290c3ad77165f071654d669691e40eab75788dd5