net: enetc: do not print error log if addr is 0

A value of 0 for addr indicates that the IEB_LBCR register does not
need to be configured, as its default value is 0. However, the driver
will print an error log if addr is 0, so this issue needs to be fixed.

Fixes: 50bfd9c06f0f ("net: enetc: set external PHY address in IERB for i.MX94 ENETC")
Signed-off-by: Wei Fang <[e-mail]>
Reviewed-by: Vladimir Oltean <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/ethernet/freescale/enetc/netc_blk_ctrl.c

···
 	}
 
 	addr = netc_get_phy_addr(np);
-	if (addr <= 0) {
+	if (addr < 0) {
 		dev_err(dev, "Failed to get PHY address\n");
 		return addr;
 	}
+
+	/* The default value of LaBCR[MDIO_PHYAD_PRTAD] is 0,
+	 * so no need to set the register.
+	 */
+	if (!addr)
+		return 0;
 
 	if (phy_mask & BIT(addr)) {
 		dev_err(dev,