drm/amdgpu/dm/mst: Remove unnecessary NULL check

kfree() checks this automatically.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
1 file changed