kernel: cleanup debug APIs

- `dbg_log` is a “NOT RECOMMENDED API”, convert the calling of this
  API to LOG_x and remove this API.

- `dbg_here`/`dbg_enter`/`dbg_exit`: no one use these APIs, remove
  them directly.

Signed-off-by: Chen Wang <unicorn_wang@outlook.com>

components/lwp/lwp.c

@@ -447,7 +447,7 @@ pid_t lwp_execve(char *filename, int debug, int argc, char **argv, char **envp)
 
     if (lwp == RT_NULL)
     {
-        dbg_log(DBG_ERROR, "lwp struct out of memory!\n");
+        LOG_E("lwp struct out of memory!\n");
         return -ENOMEM;
     }
     LOG_D("lwp malloc : %p, size: %d!", lwp, sizeof(struct rt_lwp));