leds: Standardise LED naming scheme

As discussed on LKML some notion of 'function' is needed in
LED naming. This patch adds this to the documentation and
standardises existing LED drivers.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
diff --git a/drivers/leds/leds-locomo.c b/drivers/leds/leds-locomo.c
index 2207335..7295f7f 100644
--- a/drivers/leds/leds-locomo.c
+++ b/drivers/leds/leds-locomo.c
@@ -43,13 +43,13 @@
 }
 
 static struct led_classdev locomo_led0 = {
-	.name			= "locomo:amber",
+	.name			= "locomo:amber:charge",
 	.default_trigger	= "sharpsl-charge",
 	.brightness_set		= locomoled_brightness_set0,
 };
 
 static struct led_classdev locomo_led1 = {
-	.name			= "locomo:green",
+	.name			= "locomo:green:mail",
 	.default_trigger	= "nand-disk",
 	.brightness_set		= locomoled_brightness_set1,
 };