msm: thermal: Add range checking for cluster_id

The cluster id flag is passed in from the userspace through ioctl
interface. Ensure correctness of cluster id to avoid out of bounds array
accesses.

CRS-fixed: 977508
Change-Id: I778b962d347b90488b983a15087b13e90ad06688
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>