printk_ratelimited(): fix uninitialized spinlock

ratelimit_state initialization of printk_ratelimited() seems broken.  This
fixes it by using DEFINE_RATELIMIT_STATE() to initialize spinlock
properly.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/kernel.h

@@ -425,10 +425,9 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
  */
 #ifdef CONFIG_PRINTK
 #define printk_ratelimited(fmt, ...)  ({				\
-	static struct ratelimit_state _rs = {		\
-		.interval = DEFAULT_RATELIMIT_INTERVAL, \
-		.burst = DEFAULT_RATELIMIT_BURST,       \
-	};                                              \
+	static DEFINE_RATELIMIT_STATE(_rs,				\
+				      DEFAULT_RATELIMIT_INTERVAL,	\
+				      DEFAULT_RATELIMIT_BURST);		\
 									\
 	if (__ratelimit(&_rs))						\
 		printk(fmt, ##__VA_ARGS__);				\