anv: Patch constant data pointers into shaders with using softpin

anv: Patch constant data pointers into shaders with using softpin

When we have softpin, we know the address of the shader constant data at
shader upload time because it's sitting at the end of the shader.  This
commit changes ANV to use patch constants to embed the address in the
shader patch the right address in at upload time.  This allows us to
avoid having to set up a UBO binding on-the-fly for shader constants.

This commit uses an A64 message but it's quite possible that we could
also use an A32 message and make the dataport do the 64-bit add for us.
However, load_global is what we have right now so it was easier to just
use that.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6244>