devel/highway: unbreak with clang 16 on i386 after bcdc19e0fb16

In file included from hwy/nanobenchmark.cc:27:
In file included from hwy/robust_statistics.h:24:
hwy/base.h:386:19: error: _Float16 is not supported on this target
using float16_t = _Float16;

^

Reported by: pkg-fallout