leds: Rename led_brightness_set() to led_set_brightness()

Rename leds external interface led_brightness_set() to led_set_brightness().
This is the second phase of the change to reduce confusion between the
leds internal and external interfaces that set brightness. With this change,
now the external interface is led_set_brightness(). The first phase renamed
the internal interface led_set_brightness() to __led_set_brightness().
There are no changes to the interface implementations.

Signed-off-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
diff --git a/drivers/leds/ledtrig-timer.c b/drivers/leds/ledtrig-timer.c
index 9010f7a..f774d05 100644
--- a/drivers/leds/ledtrig-timer.c
+++ b/drivers/leds/ledtrig-timer.c
@@ -104,7 +104,7 @@
 	}
 
 	/* Stop blinking */
-	led_brightness_set(led_cdev, LED_OFF);
+	led_set_brightness(led_cdev, LED_OFF);
 }
 
 static struct led_trigger timer_led_trigger = {