msm: lpm-levels: Fix issue with coresight save/restore

The coresight save/restore functions needs to be called when the L2 of the
respective clusters are placed in power collapse/GDHS. On a multi-cluster
system, keeping track of this using a static variable could result in
incorrect save/restore of CTI registers. Fix by using a variable
associated with a cluster.

Change-Id: Ib4ba5790af2a9e3bc245f1ef5010930b5cf4921c
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>