Thanks for your reply.
I don't know what was wrong with my GIT but have re-based everything from the scratch and all are good now.
However, I am using my own Ubuntu 16.04 LTS rootfs.I am not using the Desktop as I use HiKey as a Server.
However, last time I had issue with GPU as Mali 450 driver was not working properly. Lightdm was crashing and didn't let X11 loads.
Does it fixed in kernel 4.4.0 our need to apply any patches to fix that? Does it need any furtur steps to add Mali Driver on top or it's already implemented in Kernel source?