lakitu: enable KVM support for x86 BUG=b/181881807 TEST=presubmit RELEASE_NOTE=Enabled KVM-based nested virtualization for the x86 architecture. Change-Id: Id754d27b6227237bec75ff859d98f0de1c052d70 Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/50469 Reviewed-by: Meena Shanmugam <meenashanmugam@google.com> Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>