thermal: adc_tm: Update threshold cross notification to thermal client

Increased resolution of mapping between raw adc code and temperature
for thermistors. Adjust thresholds written to ensure interrupts get
triggered correctly for temperatures read.
In addition, measure temperature causing threshold violation and
provide it directly to thermal framework instead of waiting for thermal
framework to read it.

Change-Id: I4330c659a91021ef44fa17c9c79e379105aa8fc3
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>