drm/amdgpu: update atomfirmware header with memory training related members(v3)

add new vram_reserve_block structure and atomfirmware_internal_constants enumeration

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Tianci.Yin <tianci.yin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>