Revert "radeonsi: set TRUNC_COORD=0 for Total War: WARHAMMER to fix it"

This reverts commit cd12fcff.

The terrain looks fine now that TRUNC_COORD=0 for textureGather().

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <!10036>