ARM: dts: msm: Configure PMIC GPIO2 pin on sdxpoorwills

PMIC GPIO2 pin is used for reading ambient thermistor.
Configure the pin as high impedence and leave it
disabled.

Change-Id: I45f2ba923ee4a56ed7772cd40a46e6519c05d15d
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>