rcu: remove duplicated include in kernel/rcupreempt.c

Removed duplicated include file <linux/rcupdate.h> in kernel/rcupreempt.c.
Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/rcupreempt.c

@@ -51,7 +51,6 @@
 #include <linux/moduleparam.h>
 #include <linux/percpu.h>
 #include <linux/notifier.h>
-#include <linux/rcupdate.h>
 #include <linux/cpu.h>
 #include <linux/random.h>
 #include <linux/delay.h>