qdev: drop unused #include "sysemu/iothread.h"

Commit 1351d1ec89eabebc9fdff20451a62c413d7accc1 ("qdev: drop iothread
property type") forgot to remove this include.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20171205133954.31006-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

hw/core/qdev-properties-system.c

@@ -22,7 +22,6 @@
 #include "qapi/visitor.h"
 #include "chardev/char-fe.h"
 #include "sysemu/tpm_backend.h"
-#include "sysemu/iothread.h"
 
 static void get_pointer(Object *obj, Visitor *v, Property *prop,
                         char *(*print)(void *ptr),