ARM: dts: msm: Add VADC batt_therm channel

Batt therm on 8x26 QRD platform uses a different
resistive divider circuit compared to other platforms.
Therefore update the batt_therm channel to use the
QRD therm's mapping table.

Change-Id: Ib517b9fbc57476826e809734fc3dfa7e001cd23e
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>