ARM: Exynos: Call cpu_pm_enter/exit in Low Power States.

In low power cpuidle states, the FPU registers get corrupted. By calling
cpu_pm_enter, the VFP module gets notified so that it saves the FPU state and
restores it from RAM the next time a thread uses it.
    
See http://forum.xda-developers.com/showthread.php?p=57637134 to http://forum.xda-developers.com/showthread.php?p=57643086.
Merge pull request #35 from Oberon00/patch-1

Fix the infamous Music/sdcard/FPU corruption bug.