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/ps2kbd.c

@@ -25,8 +25,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#include <sys/types.h>
 #include <assert.h>
 #include <stdbool.h>
 #include <stdio.h>