drm/amdgpu:insert TMZ_BEGIN

FRAME_CONTROL(begin) is needed for vega10 due to ucode logic change,
it can fix some CTS random fail under gfx preemption enabled mode.

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>