target/s390x: Always use cpu_atomic_cmpxchgl_be_mmu in do_csst

Eliminate the CONFIG_USER_ONLY specialization.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/s390x/tcg/mem_helper.c

@@ -1800,13 +1800,7 @@ static uint32_t do_csst(CPUS390XState *env, uint32_t r3, uint64_t a1,
             uint32_t ov;
 
             if (parallel) {
-#ifdef CONFIG_USER_ONLY
-                uint32_t *haddr = g2h(env_cpu(env), a1);
-                ov = qatomic_cmpxchg__nocheck(haddr, cv, nv);
-#else
-                MemOpIdx oi = make_memop_idx(MO_TEUL | MO_ALIGN, mem_idx);
-                ov = cpu_atomic_cmpxchgl_be_mmu(env, a1, cv, nv, oi, ra);
-#endif
+                ov = cpu_atomic_cmpxchgl_be_mmu(env, a1, cv, nv, oi4, ra);
             } else {
                 ov = cpu_ldl_mmu(env, a1, oi4, ra);
                 cpu_stl_mmu(env, a1, (ov == cv ? nv : ov), oi4, ra);