lang/luajit-openresty: fix build on powerpc64

Upstream now supports powerpc64.
It was implemented in https://github.com/openresty/luajit2/commit/2763a421d6219c8cb2bbd39246de619dc796bab6,
but https://github.com/openresty/luajit2/commit/981ec8d2aac5cac76bdedd4015b6d32447b29597 is also necessary (the former commit partially adds code that the latter one removes).
This fixes powerpc64.

PR: 249156
Approved by: mm (maintainer timeout)