printk_ratelimit() functions should use CONFIG_PRINTK

Makes an embedded image a bit smaller.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/printk.c

@@ -1251,6 +1251,7 @@ void tty_write_message(struct tty_struct *tty, char *msg)
 	return;
 }
 
+#if defined CONFIG_PRINTK
 /*
  * printk rate limiting, lifted from the networking subsystem.
  *
@@ -1320,3 +1321,4 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 	return false;
 }
 EXPORT_SYMBOL(printk_timed_ratelimit);
+#endif