ssd0323: put it into the 'display' category

The category of the ssd0323 device is not set, put it into the 'display'
category.

Signed-off-by: Gan Qixin <ganqixin@huawei.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20201112125824.763182-2-ganqixin@huawei.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

hw/display/ssd0323.c

@@ -370,6 +370,7 @@ static void ssd0323_class_init(ObjectClass *klass, void *data)
     k->transfer = ssd0323_transfer;
     k->cs_polarity = SSI_CS_HIGH;
     dc->vmsd = &vmstate_ssd0323;
+    set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
 }
 
 static const TypeInfo ssd0323_info = {