Version restrictions for stable patch "drm/vmwgfx: Fix black screen and device errors when running without fbdev"

commit 140bcaa23a1c37b694910424075a15e009120dbe upstream.

Unfortunately, I forgot to add a stable version tag for this commit.

The commit is functionally suitable for versions 4.12 and above.

While it *may* apply on earlier versions, that's not intended and will most likely cause dereferences of NULL function pointers.

Thanks,

Thomas