ARM: dts: msm: Move thermal zone configs to sdm670 thermal devicetree file

Add target specific thermal devicetree file for thermal and limits
related device tree configuration for sdm670. Move all thermal zone
configuration for sdm670 to new thermal devicetree file.

Change-Id: Id0dcd2b9ffeb79e92a39816ccb80fb936273b4ec
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>