ir3: Don't emit barriers for make_available/make_visible

ir3: Don't emit barriers for make_available/make_visible

When looking at the output of some CTS tests, I realized that the
barriers vtn currently inserts to emulate coherent memory accesses
were being turned into fences, even though we never needed to do
anything special for coherent accesses before so presumably accesses are
already cache-coherent by default. Ignore make_visible/make_available
semantics to get us back to parity with the old path.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13599>