scripts: snapshot of kernel build utility scripts

This is a snapshot of build scripts taken as of msm-4.9 commit
<ed98af78b1815a8> (" Merge "drm/msm/dsi-staging: toggle phy reset
disable during idle pc") into msm-next.

Update build-all.py to compile sdm855 target.

Change-Id: If63adb69134f63db9df1160a3e7035a24b001d3d
Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>
Signed-off-by: Runmin Wang <runminw@codeaurora.org>