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/configs/turris_omnia_defconfig b/configs/turris_omnia_defconfig
index 9753e27..225a76f 100644
--- a/configs/turris_omnia_defconfig
+++ b/configs/turris_omnia_defconfig
@@ -96,6 +96,7 @@
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SPI_FLASH_MTD=y
+CONFIG_PHY_ANEG_TIMEOUT=8000
 CONFIG_PHY_MARVELL=y
 CONFIG_PHY_FIXED=y
 CONFIG_DM_DSA=y