power: qpnp-linear-charger: Add over temperature irq handler

Over-temperature interrupt triggers when temperature of the
charger crosses threshold.
Add a handler to log message for this event.

Change-Id: Ia64a71528515820f67101b9490c9513a180c0fc8
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>