This fixes a bug uncovered by:
2412c4c81e
util: Make CLAMP turn NaN into MIN.
Cc: 17.2 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
(cherry picked from commit 433f6f7ac9)