core: cacheline.hh: use the correct macro for PPC64 platform
core: cacheline.hh: use the correct macro for PPC64 platform

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

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