system/runstate: Remove unused 'qemu/plugin.h' header

system/runstate.c never required "qemu/plugin.h".

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240528145953.65398-2-philmd@linaro.org>
1 file changed