core_ctl: Add check for available cpus before accessing per_cpus

For qultivate target its trying to call per_cpu() for
cpu's which are fused out and leading to crash So, Add
a check for available cpu's before calling per_cpu.

Change-Id: Idfd97fcfc83baa59afe9010396e7b6314087bf13
Signed-off-by: Avaneesh Kumar Dwivedi <quic_akdwived@quicinc.com>
Signed-off-by: Chetan C R <quic_cchinnad@quicinc.com>