sysbus: Tidy up sysbus_init_child_obj()'s @childsize arg, part 2

sysbus: Tidy up sysbus_init_child_obj()'s @childsize arg, part 2

The callers of sysbus_init_child_obj() commonly pass either &child,
sizeof(child), or pchild, sizeof(*pchild).  Tidy up the few that use
something else instead, mostly to keep future commits simpler.

Coccinelle script:

    @@
    expression parent, propname, type;
    expression child;
    type T;
    T proxy;
    @@
    (
         sysbus_init_child_obj(parent, propname, &child, sizeof(child), type)
    |
         sysbus_init_child_obj(parent, propname, child, sizeof(*child), type)
    |
    -    sysbus_init_child_obj(parent, propname, child, sizeof(proxy), type)
    +    sysbus_init_child_obj(parent, propname, child, sizeof(*child), type)
    )

This script is *unsound*: for each change we need to verify the
@childsize argument stays the same.  I did.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-44-armbru@redhat.com>