Note that static hints no longer break loader hints

This commentary was carried over from the x86 version of the same code,
but has actually been inaccurate for a while now. As of FreeBSD 12.x,
all environments are used unless they disable each other. See
39d44f7f15c ("kern_environment: use any provided environments [...]")
for details.

Reviewed by: imp
Differentiala Revision: https://reviews.freebsd.org/D35695