drm/amdgpu: set preferred_domain independent of fallback handling

When GEM needs to fallback to GTT for VRAM BOs we still want the
preferred domain to be untouched so that the BO has a cance to move back
to VRAM in the future.

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>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
index e9a21d9..540e03f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
@@ -37,6 +37,7 @@ struct amdgpu_bo_param {
 	unsigned long			size;
 	int				byte_align;
 	u32				domain;
+	u32				preferred_domain;
 	u64				flags;
 	enum ttm_bo_type		type;
 	struct reservation_object	*resv;