hw/m68k/mcf_intc: Expose MMIO region via SysBus API

QOM objects shouldn't access each other internals fields
except using the QOM API.

Here the caller of mcf_intc_init() access the MMIO region from
the MCF_INTC state. Avoid that by exposing that region via
sysbus_init_mmio(), then get it with sysbus_mmio_get_region().

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Thomas Huth <huth@tuxfamily.org>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Message-ID: <20231024083010.12453-4-philmd@linaro.org>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>
diff --git a/hw/m68k/mcf_intc.c b/hw/m68k/mcf_intc.c
index 4cd3018..1f74ea0 100644
--- a/hw/m68k/mcf_intc.c
+++ b/hw/m68k/mcf_intc.c
@@ -173,6 +173,7 @@
     mcf_intc_state *s = MCF_INTC(obj);
 
     memory_region_init_io(&s->iomem, obj, &mcf_intc_ops, s, "mcf", 0x100);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->iomem);
 }
 
 static void mcf_intc_class_init(ObjectClass *oc, void *data)
@@ -211,7 +212,8 @@
     s = MCF_INTC(dev);
     s->cpu = cpu;
 
-    memory_region_add_subregion(sysmem, base, &s->iomem);
+    memory_region_add_subregion(sysmem, base,
+                                sysbus_mmio_get_region(SYS_BUS_DEVICE(dev), 0));
 
     return qemu_allocate_irqs(mcf_intc_set_irq, s, 64);
 }