The current code was spreaded over power and powermgmt which made
it behave strangely, especially since there are relationships
between power management and frequency scaling. The new code makes
sure power management is initialised before frequency scaling
starts. It also makes sure to start from a known state, thus
fixing potential issue when the bootloader stops in a trickle
state where DCDC is improperly configured.
Change-Id: Ibded2e590e108f6c98daa52d2cf1bd28763c8923