core_ctl: Keep all CPUs un-isolated while boost is active

Currently BIG cluster CPUs are kept active while boost is enabled.
If core_ctl is used for the little cluster, these CPUs can be
isolated. Keeping all CPUs active during boost is desired for the
best performance.

Change-Id: Icacb99a08335b3a3038db202227e69e06009ae49
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>