ARM: dts: msm: add temperature alarm ADC configurations for PM8998

Specify VADC configurations for the PM8998 temperature alarm
peripheral so that it is able to read the true PMIC die
temperature instead of estimating it based on the over-
temperature stage.

Change-Id: Ice0bf4de25ffdcfff23817736cd1c21ac91567a2
Signed-off-by: David Collins <collinsd@codeaurora.org>