drm/amdgpu: unbind GTT only when it is bound

Doesn't make much sense to clear the GTT when it was never filled.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed