thread: complete the "core/thread: Fix unwind information for seastar threads" to work on PPC
thread: complete the "core/thread: Fix unwind information for seastar threads" to work on PPC

Add the corresponding PPC-specific assembly line.

Signed-off-by: Vlad Zolotarov <976c0f8d0852ed6439ad273880b400a75a7c41d0@scylladb.com>

avikivity/seastar,syuu1228/seastar,dreamsxin/seastar,syuu1228/seastar,scylladb/seastar,syuu1228/seastar,scylladb/seastar,scylladb/seastar,avikivity/seastar,cloudius-systems/seastar,cloudius-systems/seastar,cloudius-systems/seastar,dreamsxin/seastar,dreamsxin/seastar,avikivity/seastar