Bump __FreeBSD_version for new <crypto/*.h> headers.

This bump covers the addition of both <crypto/chacha20_poly1305.h> and
<crypto/curve25519.h>.

Sponsored by: The FreeBSD Foundation

(cherry picked from commit dd2f7a4b45eb1285e710cfce60cb77f7c11f8075)
(cherry picked from commit 2c4b65cc3d227f31864e183c15f6c42e2c596cd9)