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/pci/virtio/virtio_block.c

@@ -26,19 +26,11 @@
  * $FreeBSD$
  */
 
-#include <sys/cdefs.h>
 #include <sys/param.h>
-#include <sys/stat.h>
-#include <sys/uio.h>
-#include <sys/ioctl.h>
 #include <errno.h>
-#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <stdint.h>
 #include <string.h>
-#include <strings.h>
-#include <unistd.h>
 #include <assert.h>
 #include <pthread.h>
 #include <openssl/md5.h>