target: Unify QOM style

Enforce the style described by commit 067109a11c ("docs/devel:
mention the spacing requirement for QOM"):

  The first declaration of a storage or class structure should
  always be the parent and leave a visual space between that
  declaration and the new code. It is also useful to separate
  backing for properties (options driven by the user) and internal
  state to make navigation easier.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-Id: <20231013140116.255-2-philmd@linaro.org>
37 files changed