pckbd: more vmstate_register() from i8042_mm_init() to i8042_mmio_realize()

Note in this case it is not possible to register a (new) VMStateDescription in
the DeviceClass without breaking migration compatibility for the MIPS magnum
machine.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20220624134109.881989-30-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index 8708595..1ab7679 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -682,6 +682,9 @@
                           "i8042", s->size);
 
     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->region);
+
+    /* Note we can't use dc->vmsd without breaking migration compatibility */
+    vmstate_register(NULL, 0, &vmstate_kbd, ks);
 }
 
 static void i8042_mmio_init(Object *obj)
@@ -723,8 +726,6 @@
     s->irq_kbd = kbd_irq;
     s->irq_mouse = mouse_irq;
 
-    vmstate_register(NULL, 0, &vmstate_kbd, s);
-
     s->kbd = ps2_kbd_init(kbd_update_kbd_irq, s);
     s->mouse = ps2_mouse_init(kbd_update_aux_irq, s);