leds: Add missing include for leds.h

This patch has added #include <linux/spinlock.h> to include/linux/leds.h
for rwlock_t.

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

include/linux/leds.h

@@ -13,6 +13,7 @@
 #define __LINUX_LEDS_H_INCLUDED
 
 #include <linux/list.h>
+#include <linux/spinlock.h>
 
 struct device;
 /*