net: fman: memac: Convert to devm_of_phy_optional_get()

Use the new devm_of_phy_optional_get() helper instead of open-coding the
same operation.

As devm_of_phy_optional_get() returns NULL if either the PHY cannot be
found, or if support for the PHY framework is not enabled, it is no
longer needed to check for -ENODEV or -ENOSYS.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/f2d801cd73cca36a7162819289480d7fc91fcc7e.1674584626.git.geert+renesas@glider.be
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: geertu

drivers/net/ethernet/freescale/fman/fman_memac.c

@@ -1152,13 +1152,12 @@ int memac_initialization(struct mac_device *mac_dev,
 	else
 		memac->sgmii_pcs = pcs;
 
-	memac->serdes = devm_of_phy_get(mac_dev->dev, mac_node, "serdes");
-	err = PTR_ERR(memac->serdes);
-	if (err == -ENODEV || err == -ENOSYS) {
+	memac->serdes = devm_of_phy_optional_get(mac_dev->dev, mac_node,
+						 "serdes");
+	if (!memac->serdes) {
 		dev_dbg(mac_dev->dev, "could not get (optional) serdes\n");
-		memac->serdes = NULL;
 	} else if (IS_ERR(memac->serdes)) {
-		dev_err_probe(mac_dev->dev, err, "could not get serdes\n");
+		err = PTR_ERR(memac->serdes);
 		goto _return_fm_mac_free;
 	}