d3d12: ensure all compoents of clip-distances are written

d3d12: ensure all compoents of clip-distances are written

This fixes a regression that happened after rebasing on master, where we
end up not writing all components of the clip-distance array, which the
DXIL validation code in the D3D12 runtime treats as an error.

To ensure we don't end up overwriting a previous wrire, enable
nir_shader_compiler_options::lower_all_io_to_temps as well.

Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7477>