drivers: thermal: qpnp-temp-alarm: Use of-thermal interface

Update PMIC temp alarm driver to use of-thermal interface to register
the PMIC die temperature sensors. This enables the thermal framework to
define the config for PMIC alarm sensors in the device tree.

PMIC temperature sensors work on predefined thresholds, so it supports
only callback to read temperature. On reaching the predefined threshold
the driver will notify the of-thermal interface to handle the trip
notification.

Change-Id: Ib1cde1edc1a970530e20d19ad041621272b1b93d
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>