d3dx9_36: D3DXQuaternionLn computes as if the norm of the input is 1

[Matteo Bruni]

2012/6/12 Nozomi Kodama <nozomi.kodama at yahoo.com>:
>
> +    if ( (pq->w >= 1.0f) || (pq->w == -1.0f) )

I think the second comparison should be '<=', if you want to avoid getting NaNs.