target/unicore32: Use env_cpu, env_archcpu

Cleanup in the boilerplate that each target must define.
Replace uc32_env_get_cpu with env_archcpu.  The combination
CPU(uc32_env_get_cpu) should have used ENV_GET_CPU to begin;
use env_cpu now.

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>

hw/unicore32/puv3.c

@@ -56,7 +56,7 @@ static void puv3_soc_init(CPUUniCore32State *env)
 
     /* Initialize interrupt controller */
     cpu_intc = qemu_allocate_irq(puv3_intc_cpu_handler,
-                                 uc32_env_get_cpu(env), 0);
+                                 env_archcpu(env), 0);
     dev = sysbus_create_simple("puv3_intc", PUV3_INTC_BASE, cpu_intc);
     for (i = 0; i < PUV3_IRQS_NR; i++) {
         irqs[i] = qdev_get_gpio_in(dev, i);