sched: replace up_cpu_index with this_cpu

Make this_cpu is arch independent and up_cpu_index do that.
In AMP mode, up_cpu_index() may return the index of the physical core.

Signed-off-by: fangxinyong <fangxinyong@xiaomi.com>

drivers/net/netdev_upperhalf.c

@@ -753,7 +753,7 @@ static inline void netdev_upper_queue_work(FAR struct net_driver_s *dev)
   FAR struct netdev_upperhalf_s *upper = dev->d_private;
 
 #ifdef CONFIG_NETDEV_WORK_THREAD
-  int cpu = up_cpu_index();
+  int cpu = this_cpu();
   int semcount;
 
   if (nxsem_get_value(&upper->sem[cpu], &semcount) == OK &&