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/core/main.c

@@ -26,10 +26,6 @@
  * $FreeBSD$
  */
 
-#include <sys/cdefs.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <sys/time.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -43,8 +39,6 @@
 #include <stdbool.h>
 #include <getopt.h>
 
-#include "types.h"
-#include "vmm.h"
 #include "vmmapi.h"
 #include "sw_load.h"
 #include "cpuset.h"