thermal: qpnp-adc: Add thermal monitoring ADC driver

The thermal monitoring QPNP ADC driver is used for
monitoring multiple channels with recurring
measurements. It configures the VADC_TM peripheral
to set voltage and temperature thresholds and
notifies clients once the thresholds are crossed.

Upto five channels can be individually configured
for input channel, interval time, low and high
threshold.

The driver is added as part of the thermal sysfs
interface to provide the thermal clients the
ability to set temperature thresholds and receive
notification. Clients can separately enable/disable
low/high temperature thresholds for notification.
Channels 3 through 5 are allocated for thermistor
channels that can be used by the thermal clients
using thermal sysfs for temperature threshold
notification.

Separate kernel api's are provided for usb_id
and batt_therm driver to set voltage and temperature
threshold notifications. TM Channels 0 and 1 are
statically mapped for usb_id and batt_therm monitoring
respectively.

Change-Id: I8de8a494d68d3b29c029fdc7d650a8b74f17a645
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>