migration/dirtyrate: simplify includes in dirtyrate.c

Remove redundant blank line which is left by Commit 662770a,
also take this opportunity to remove redundant includes in dirtyrate.c.

Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
Message-Id: <1604030281-112946-1-git-send-email-zhengchuan@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

migration/dirtyrate.c

@@ -11,17 +11,12 @@
  */
 
 #include "qemu/osdep.h"
-
 #include <zlib.h>
 #include "qapi/error.h"
 #include "cpu.h"
-#include "qemu/config-file.h"
-#include "exec/memory.h"
 #include "exec/ramblock.h"
-#include "exec/target_page.h"
 #include "qemu/rcu_queue.h"
 #include "qapi/qapi-commands-migration.h"
-#include "migration.h"
 #include "ram.h"
 #include "trace.h"
 #include "dirtyrate.h"