aco: disable zero offset optimization for strict WQM coords

aco: disable zero offset optimization for strict WQM coords

If we try to do this, we end up using {undef,coordx} as the coordinates
for an image_sample instruction, because we can't shrink the linear VGPR.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9767
Fixes: 859e059aa912 ("radv: use fix_derivs_in_divergent_cf")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25477>