leds: wago-m4: demote 'RPMsg channel not available' to dev_dbg

The message fired as dev_err_ratelimited during the normal window
between probe() and RPMsg channel announcement (trigger active,
rpdev not yet set). This is expected behaviour, not an error.

Demote to dev_dbg to keep the kernel log clean on every boot.

Signed-off-by: Heinrich Toews <ht@twx-software.de>

drivers/leds/rgb/wago-m4-led-wrapper.c

@@ -214,7 +214,7 @@ static int wago_send(struct wago_m4_led_priv *priv,
 	int ret, tries;
 
 	if (!priv->rpdev) {
-		dev_err_ratelimited(priv->dev, "RPMsg channel not available\n");
+		dev_dbg(priv->dev, "RPMsg channel not yet available, dropping frame\n");
 		return -ENODEV;
 	}