libpower: cleanup

*Remove timer/sampling rate management.
*Use appropriate value for interactive hispeed_freq.
*Permissions for boostpulse nodes already set in init.cm.rc.

Change-Id: If0275c43cf07836bbed3e27f13740bd1ea0a20c3
recovery: remove prebuilt kernel and custom graphics

Change-Id: I3a45fd6afe8e682eba3457fcf317aaecbbe637bd