hwpstate_amd: add amd pstate for zen4

Co-authored-by: Daniel Schaefer <dhs@frame.work>
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: Framework Computer Inc
Differential Revision: https://reviews.freebsd.org/D48461

(cherry picked from commit 621569254cd0b0639488aa5d7b8143cef7c90a18)