ARM: dts: msm: Update chg_temp channel property for pmithorium

Update chg_temp channel scale-function property for pmithorium
such that charger temperature channel returns temperature in
units of millidegC.

Change-Id: I6e125444141286602e8727ee480001a50790ac5d
Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>