sched: Add snapshot of core_ctl

This snapshot is taken from msm-4.14 as of commit 3206cd0e936a9f1
("sched: core_ctl: Add core_ctl_notifier_register()").

Change-Id: Icc082b55d620739e0e6be1c24e7506221cd5cfd9
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>