OpenSSL assumes AT_HWCAP = 16 (as on Linux), but on FreeBSD AT_HWCAP = 25
Switch to using AT_HWCAP, and setting it to 16 if it is not defined.
CLA: trivial
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17090)