util/cacheflush: Use declarations from <OSCacheControl.h> on Darwin

Per the cache(3) man page, sys_icache_invalidate() and
sys_dcache_flush() are declared in <libkern/OSCacheControl.h>.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230605175647.88395-2-philmd@linaro.org>
1 file changed