tu: Remove useless post-binning flushes

tu: Remove useless post-binning flushes

The Vulkan blob doesn't do this, and based on my understanding of how
the blob works this is unnecessary. CACHE_FLUSH is already serialized
against all 3d commands so you don't need to wait for rendering commands
to finish before issuing it, and the subsequent wfi + WAIT_FOR_ME will
cause the CP to wait for the CACHE_FLUSH to finish, so there's also no
need to wait for it to complete. The CACHE_INVALIDATE also seems
unnecessary, and also isn't done by the blob.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4964>