cpu: Introduce cpu_set_cpustate_pointers

Consolidate some boilerplate from foo_cpu_initfn.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/sh4/cpu.c

@@ -194,11 +194,10 @@ static void superh_cpu_realizefn(DeviceState *dev, Error **errp)
 
 static void superh_cpu_initfn(Object *obj)
 {
-    CPUState *cs = CPU(obj);
     SuperHCPU *cpu = SUPERH_CPU(obj);
     CPUSH4State *env = &cpu->env;
 
-    cs->env_ptr = env;
+    cpu_set_cpustate_pointers(cpu);
 
     env->movcal_backup_tail = &(env->movcal_backup);
 }