serial: 8250_bcm2835aux: Suppress register_port error on -EPROBE_DEFER

Suppress a gratuitous error message if serial8250_register_8250_port()
returns -EPROBE_DEFER.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/6aea0eacf3bfa73fe2d81082cc723265413410c8.1579175223.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_bcm2835aux.c

@@ -95,8 +95,9 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 	/* register the port */
 	ret = serial8250_register_8250_port(&data->uart);
 	if (ret < 0) {
-		dev_err(&pdev->dev, "unable to register 8250 port - %d\n",
-			ret);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev,
+				"unable to register 8250 port - %d\n", ret);
 		goto dis_clk;
 	}
 	data->line = ret;