ARM: dts: msm: Remove support for XO_THERM for kona

XO_THERM is not present on PM8150 and needs to be read
from PMx55 instead. Remove support in ADC_TM driver to read
XO_THERM channel through thermal zones.

Change-Id: Id98856400b5a4e92023c56a025019cd239c69ed4
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>