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/lm32/cpu.c

@@ -142,11 +142,10 @@ static void lm32_cpu_realizefn(DeviceState *dev, Error **errp)
 
 static void lm32_cpu_initfn(Object *obj)
 {
-    CPUState *cs = CPU(obj);
     LM32CPU *cpu = LM32_CPU(obj);
     CPULM32State *env = &cpu->env;
 
-    cs->env_ptr = env;
+    cpu_set_cpustate_pointers(cpu);
 
     env->flags = 0;
 }