Fix uninitialized variables in rsaz-3k-avxifma & rsaz-4k-avxifma

Fix uninitialized variables in rsaz-3k-avxifma & rsaz-4k-avxifma
assembler.

This looks like a block copy bug, the 2k file uses both fields but the
3k & 4K variants only pass acc0_0 to functions.

Reported and proposed fix supplied by pyca (@reaperhulk and @alex).

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
MergeDate: Fri Mar 13 08:48:11 2026
(Merged from https://github.com/openssl/openssl/pull/30061)