ARM: dts: msm: Update VADC nodes for SDM845

Remove registering VADC nodes with thermal
sysfs since these nodes are exposed to
thermal zone through the ADC TM nodes.

Change-Id: Ie5a10502dcfcaef4a894000b438b5d7a14a17cc9
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>