led: include cyclic.h in led_sw_blink.c

This makes use of the cyclic API but relies on implicitly getting the
appropriate declarations through some nested include. Include the
cyclic.h header directly.

Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>

drivers/led/led_sw_blink.c

@@ -5,6 +5,7 @@
  * Author: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
  */
 
+#include <cyclic.h>
 #include <dm.h>
 #include <led.h>
 #include <time.h>