drm/amdgpu: add gart recovery by gtt list V2

V2:
a. gart recovery should be ahead of ring test.
b. rename to amdgpu_ttm_recover_gart

Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>