omap: Fix compile dependency to LEDS_CLASS

If we LEDS_CLASS is not selected, we will get undefined reference
to `led_classdev_register'.
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/plat-omap/Kconfig

@@ -33,7 +33,7 @@ config OMAP_DEBUG_DEVICES
 config OMAP_DEBUG_LEDS
 	bool
 	depends on OMAP_DEBUG_DEVICES
-	default y if LEDS
+	default y if LEDS_CLASS
 
 config OMAP_RESET_CLOCKS
 	bool "Reset unused clocks during boot"