core_ctl: fix bug in assignment of not_preferred tunable values

Cluster's lru list is iterated while storing the not_preferred
tunable values. The position of a CPU in this list gets changed
when it is isolated. This results in an incorrect assignment of
user input. Fix this by iterating the CPUs serially in a cluster.

Change-Id: Id528e9daef9653b402720f815aa786e59f6f09fb
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>