msm: thermal: Update cluster info only if sync cluster DT is defined

KTM checks cpu topology info for all targets irrespective of
cluster or non cluster targets which will leads unexpected behaviour
for non cluster targets. Configure cluster related info only if
"qcom,synchronous-cluster-id" DT node is defined.

Change-Id: Icb460c40f9d3d1733aabe635f0f42bbedad17a81
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>