on affected platforms (PowerPC and AArch64).
For reference, minimalistic #ifdef GHASH is sufficient, because
it's never defined with OPENSSL_SMALL_FOOTPRINT and ctx->ghash
is never referred.
Reviewed-by: Rich Salz <rsalz@openssl.org>
(cherry picked from commit b2991c081aba5351a3386bdde2927672d53e5c99)