sched: integrate core_ctl with EAS

- CPUFREQ_LOAD_CHANGE notification is not available in EAS. Query
the load directly from scheduler from tick callback.

- core_ctl depends on cpufreq policy to populate clusters. This is
the last piece remaining in core_ctl that depends on cpufreq. Remove
this dependency also by populating the clusters based on topology.

Change-Id: I92402e583bdcc001fdae0a086fdc38acf34fe35d
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>