leds: Include linux/of.h header

'of_match_ptr' is defined in linux/of.h. Include it explicitly.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
diff --git a/drivers/leds/leds-ns2.c b/drivers/leds/leds-ns2.c
index 141f134..c7a4230 100644
--- a/drivers/leds/leds-ns2.c
+++ b/drivers/leds/leds-ns2.c
@@ -30,6 +30,7 @@
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/platform_data/leds-kirkwood-ns2.h>
+#include <linux/of.h>
 #include <linux/of_gpio.h>
 
 /*