share/mk/bsd.cpu.mk: Add AMD Zen 4 for x86

Main difference between older Zen variants is that this supports AVX-512

Reviewed by: imp (previous version), emaste
Approved by: emaste
Differential Revision: https://reviews.freebsd.org/D41331

(cherry picked from commit ed3fb74e44b9ef37837cebc5acfd7e68867206ca)