rwlock: get rid of SEASTAR_DEBUG_LOCKING
rwlock: get rid of SEASTAR_DEBUG_LOCKING

It is used inconsistently and the asserts it enables
are lightweight and can be evaluated unconditionally.

Signed-off-by: Benny Halevy <23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>

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