accel: Make accel-blocker.o target agnostic

accel-blocker.c is not target specific, move it to system_ss[].

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Message-Id: <20230914185718.76241-5-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
1 file changed