WinARM64 issue

Hello. I just updated the NRD library in our game, and with it, the MathLib. With the update MathLib can't be compiler anymore on WinARM64.

Functions like this are not compiling
```
    ML_INLINE float16_t2(const float16_t& x, const float16_t& y)
        : x(x.x), y(y.x) {
    }
```
because float16_t is __fp16 which has no .x member. 