msm-core: Activate ptable only on userspace power update

The power numbers calculated for cpus during probe are the same between
different cpus. This might cause the scheduler to incorrectly place
little tasks on big cpus and vice versa. Wait until the userspace
updates the device specific power numbers and then update the ptable to
reflect the non-overlapping power numbers between the clusters.

Change-Id: Icecda836d474d30a61118b1c5f4ebe6f3509a312
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>