plugins: distinct types for callbacks

plugins: distinct types for callbacks

To prevent errors when writing new types of callbacks or inline
operations, we split callbacks data to distinct types.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240502211522.346467-8-pierrick.bouvier@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240514174253.694591-10-alex.bennee@linaro.org>