ARM: dts: msm: Update ADC thermistors exposed in lito

Remove conn_therm from PM7250 ADC_TM as it is not required for
thermal mitigation. Add mmw-pa4-usr thermistor under default
ADC_TM entry for PM7250.

Change-Id: I985e4a068693ff92f3c2b287379c7f23f7245cfb