drm/amdgpu: fix null pointer by previous cleanup
drm/amdgpu: fix null pointer by previous cleanup

Signed-off-by: Chunming Zhou <331ec51bea57dab96050040a347da39906b1207b@amd.com>
Reviewed-by: Christian K?nig <c7ea837d7a46effe4232b086213468b8b31643bf@amd.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs