cmd: led: fix led command usage for the LED_SW_BLINK enabled case

CONFIG_LED_BLINK and CONFIG_LED_SW_BLINK can be defined independently.
Led blinking works if any (or both) of them is enabled. Unfortunately
the led command help does not display blinking option if only
CONFIG_LED_SW_BLINK is enabled. This is definitely wrong.

This patch fix an issue.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy@iopsys.eu>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Alexander Dahl <ada@thorsis.com>
diff --git a/cmd/led.c b/cmd/led.c
index 2f786f3..91fb856 100644
--- a/cmd/led.c
+++ b/cmd/led.c
@@ -118,7 +118,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_LED_BLINK
+#if defined(CONFIG_LED_BLINK) || defined(CONFIG_LED_SW_BLINK)
 #define BLINK "|blink [blink-freq in ms]"
 #else
 #define BLINK ""