net: phy: Replace PHY_ANEG_TIMEOUT with Kconfig symbol

Switch PHY_ANEG_TIMEOUT to CONFIG_PHY_ANEG_TIMEOUT Kconfig symbol.
This removes one more configuration headers option finalizes its
Kconfig symbol conversion. No functional change expected.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/net/xilinx_axi_emac.c b/drivers/net/xilinx_axi_emac.c
index a1a39f6..4d87e2d 100644
--- a/drivers/net/xilinx_axi_emac.c
+++ b/drivers/net/xilinx_axi_emac.c
@@ -361,7 +361,7 @@
 	 * and the external PHY is not obtained.
 	 */
 	debug("axiemac: waiting for link status of the PCS/PMA PHY");
-	while (retry_cnt * 10 < PHY_ANEG_TIMEOUT) {
+	while (retry_cnt * 10 < CONFIG_PHY_ANEG_TIMEOUT) {
 		rc = phyread(priv, priv->pcsaddr, MII_BMSR, &mii_reg);
 		if ((mii_reg & BMSR_LSTATUS) && mii_reg != 0xffff && !rc) {
 			debug(".Done\n");