linux-user/arm: Implement __kernel_memory_barrier

This fallback syscall was stubbed out.
It would only matter for emulating pre-armv6.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220323005839.94327-2-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
1 file changed