ARM: dts: msm: Move various nodes under /vendor on SDM845

Move a few nodes under /vendor path. This will allow them to be
properly overlayed from the board overlay files. Also disable compilation
of complete board dtbs if dtb overlay is enabled.

Change-Id: I78b15ee9540aa0b2654ef9edbf890bb90198a63c
Signed-off-by: Kyle Yan <kyan@codeaurora.org>