display/sm501 display/ati: Fix to realize "i2c-ddc"

sm501_init() and ati_vga_realize() create an "i2c-ddc" device, but
neglect to realize it.  Affects machines sam460ex, shix, r2d, and
fulong2e.

In theory, a device becomes real only on realize.  In practice, the
transition from unreal to real is a fuzzy one.  The work to make a
device real can be spread between realize methods (fine),
instance_init methods (wrong), and board code wiring up the device
(fine as long as it effectively happens on realize).  Depending on
what exactly is done where, a device can work even when we neglect
to realize it.

This one appears to work.  Nevertheless, it's a clear misuse of the
interface.  Even when it works today (more or less by chance), it can
break tomorrow.

Fix by realizing it right away.  Visible in "info qom-tree"; here's
the change for sam460ex:

     /machine (sam460ex-machine)
       [...]
       /unattached (container)
         [...]
    -    /device[14] (sii3112)
    +    /device[14] (i2c-ddc)
    +    /device[15] (sii3112)
         [rest of device[*] renumbered...]

Fixes: 4a1f253adb45ac6019971193d5077c4d5d55886a
Fixes: c82c7336de58876862e6b4dccbda29e9240fd388
Cc: BALATON Zoltan <balaton@eik.bme.hu>
Cc: qemu-ppc@nongnu.org
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Cc: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Tested-by: BALATON Zoltan <balaton@eik.bme.hu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200609122339.937862-19-armbru@redhat.com>

hw/display/ati.c

@@ -935,6 +935,8 @@ static void ati_vga_realize(PCIDevice *dev, Error **errp)
     bitbang_i2c_init(&s->bbi2c, i2cbus);
     I2CSlave *i2cddc = I2C_SLAVE(qdev_create(BUS(i2cbus), TYPE_I2CDDC));
     i2c_set_slave_address(i2cddc, 0x50);
+    object_property_set_bool(OBJECT(i2cddc), true, "realized",
+                             &error_abort);
 
     /* mmio register space */
     memory_region_init_io(&s->mm, OBJECT(s), &ati_mm_ops, s,

hw/display/sm501.c

@@ -1833,6 +1833,8 @@ static void sm501_init(SM501State *s, DeviceState *dev,
     /* ddc */
     I2CDDCState *ddc = I2CDDC(qdev_create(BUS(s->i2c_bus), TYPE_I2CDDC));
     i2c_set_slave_address(I2C_SLAVE(ddc), 0x50);
+    object_property_set_bool(OBJECT(ddc), true, "realized",
+                             &error_abort);
 
     /* mmio */
     memory_region_init(&s->mmio_region, OBJECT(dev), "sm501.mmio", MMIO_SIZE);