qga: move declare of QGAConfig struct to top of file

qga: move declare of QGAConfig struct to top of file

It is referenced by QGAState already, and it is clearer to declare all
data types at the top of the file, rather than have them mixed with
code later.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-ID: <20240712132459.3974109-20-berrange@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>