v3dv: disable depth/stencil testing if we don't have a depth/stencil attachment

Also, remove obsolete FIXME.

Fixes:
dEQP-VK.fragment_operations.early_fragment.early_fragment_tests_stencil_no_attachment

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
1 file changed