r600/sfn: Handle mem barrier and image barrier by using ACK

When reading from and writing to the same image in a shader the
memory_barrier can possibly be handled by emitting an ack-write and then
wait for the ack when the memory barrier is set.

Not sure whow well this goes with the syncronization across all shader
invocations though.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7142>
4 files changed