Add MAX_CONTROLLER_LEDS constant

Change-Id: I5ec972338c50647049bb5a8279847d54a84d9f70
diff --git a/include/input/Input.h b/include/input/Input.h
index 600c10e..37f3b72 100644
--- a/include/input/Input.h
+++ b/include/input/Input.h
@@ -90,6 +90,9 @@
     ALED_CONTROLLER_4 = 0x13,
 };
 
+/* Maximum number of controller LEDs we support */
+#define MAX_CONTROLLER_LEDS 4
+
 /*
  * SystemUiVisibility constants from View.
  */