net: dwmac_socfpga: initialize local data for mdio regmap configuration

Explicitly zero-ize the local mdio_regmap_config data, and explicitly
set the .autoscan parameter, as we only have a PCS on this bus.

Fixes: 5d1f3fe ("net: stmmac: dwmac-sogfpga: use the lynx pcs driver")
Suggested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Suggested-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
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/stmicro/stmmac/dwmac-socfpga.c

@@ -389,7 +389,6 @@ static int socfpga_dwmac_probe(struct platform_device *pdev)
 	struct net_device	*ndev;
 	struct stmmac_priv	*stpriv;
 	const struct socfpga_dwmac_ops *ops;
-	struct regmap_config pcs_regmap_cfg;
 
 	ops = device_get_match_data(&pdev->dev);
 	if (!ops) {
@@ -447,19 +446,22 @@ static int socfpga_dwmac_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_dvr_remove;
 
-	memset(&pcs_regmap_cfg, 0, sizeof(pcs_regmap_cfg));
-	pcs_regmap_cfg.reg_bits = 16;
-	pcs_regmap_cfg.val_bits = 16;
-	pcs_regmap_cfg.reg_shift = REGMAP_UPSHIFT(1);
-
 	/* Create a regmap for the PCS so that it can be used by the PCS driver,
 	 * if we have such a PCS
 	 */
 	if (dwmac->tse_pcs_base) {
+		struct regmap_config pcs_regmap_cfg;
 		struct mdio_regmap_config mrc;
 		struct regmap *pcs_regmap;
 		struct mii_bus *pcs_bus;
 
+		memset(&pcs_regmap_cfg, 0, sizeof(pcs_regmap_cfg));
+		memset(&mrc, 0, sizeof(mrc));
+
+		pcs_regmap_cfg.reg_bits = 16;
+		pcs_regmap_cfg.val_bits = 16;
+		pcs_regmap_cfg.reg_shift = REGMAP_UPSHIFT(1);
+
 		pcs_regmap = devm_regmap_init_mmio(&pdev->dev, dwmac->tse_pcs_base,
 						   &pcs_regmap_cfg);
 		if (IS_ERR(pcs_regmap)) {
@@ -470,6 +472,7 @@ static int socfpga_dwmac_probe(struct platform_device *pdev)
 		mrc.regmap = pcs_regmap;
 		mrc.parent = &pdev->dev;
 		mrc.valid_addr = 0x0;
+		mrc.autoscan = false;
 
 		snprintf(mrc.name, MII_BUS_ID_SIZE, "%s-pcs-mii", ndev->name);
 		pcs_bus = devm_mdio_regmap_register(&pdev->dev, &mrc);