sync switch buffer scheme with windows kmd for gfx v8,
step2:
Insert 128NOP after&before VM flush to prevent CE vm fault.
Signed-off-by: NMonk Liu <Monk.Liu@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>