net: altera_tse: explicitly disable autoscan on the regmap-mdio bus

Set the .autoscan flag to false on the regmap-mdio bus, to avoid using a
random uninitialized value. We don't want autoscan in this case as the
mdio device is a PCS and not a PHY.

Fixes: db48abba ("net: ethernet: altera-tse: Convert to mdio-regmap and use PCS Lynx")
Suggested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/altera/altera_tse_main.c

@@ -1288,6 +1288,7 @@ static int altera_tse_probe(struct platform_device *pdev)
 	mrc.regmap = pcs_regmap;
 	mrc.parent = &pdev->dev;
 	mrc.valid_addr = 0x0;
+	mrc.autoscan = false;
 
 	/* Rx IRQ */
 	priv->rx_irq = platform_get_irq_byname(pdev, "rx_irq");