DM: cleanup for header inclusions

used https://gitlab.com/esr/deheader to detect and remove unnecessary
header file inclusions

Signed-off-by: Zide Chen <zide.chen@intel.com>

devicemodel/hw/platform/cmos_io.c

@@ -26,10 +26,6 @@
  */
 
 #include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <signal.h>
-#include <time.h>
 #include <assert.h>
 
 #include "inout.h"