util: fix msvc build
Fix msvc build regression after 0536b691 reported by Prodea Alexandru-Liviu. Closes: mesa/mesa#6137 Fixes: 0536b691 ("util: fix build with clang 10 on mips64") Reviewed-by:Ilia Mirkin <imirkin@alum.mit.edu> Part-of: <mesa/mesa!15355> (cherry picked from commit e50eb1ce)