Use generic atomic implementation based on cmpxchg. So remove csky asm/atomic.h. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@kernel.org> Cc: Paul E. McKenney <paulmck@kernel.org>