This splits the common write callback into separate ast2400 and ast2500
implementations. This makes it clearer when implementing differing
behaviour.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200121013302.43839-2-joel@jms.id.au
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>