[Intel-gfx] Building GVT-g as a sub-module of i915

[Wang, Zhi A]

Hi Guys:
  I'm trying to make GVT-g as a sub-module of i915 in the next version patchset. The basic idea is to introduce a "gvt-g pre-enabled state" in i915. I think it should be a kernel option.

When this kernel option is enabled by user, i915 will do GGTT partition and save HW initial MMIO snapshot for gvt-g module during loading.
When GVT-g modules is loaded, first it should check if the "gvt-g pre-eanbled state" is enabled in i915. If yes, then it will use the snapshot in i915 and continue to load. If no, then bail out.

Thanks,
Zhi.