ARM: dts: msm: Update ADC support for SDM450

Add thermal_zones entries for ADC channels that register in
thermal framework, to prevent registration failure in
PM8953 in SDM450.

Change-Id: Ia0cd7dec8e328cacd47f25724ea697fba24dfffb
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>