thermal: qpnp-adc-tm: Add die_temp debug logs

Add more die_temp debug logs and fix the units for
converting millidegC to K during reverse calibration.
Also add bound checks in the status read to prevent
spurious interrupts.

Change-Id: I888216383ae9e8aed83bc5b22b4e36499b500c11
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>