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/clearfog_spi_defconfig b/configs/clearfog_spi_defconfig
index 4175fdb17..f345b12 100644
--- a/configs/clearfog_spi_defconfig
+++ b/configs/clearfog_spi_defconfig
@@ -65,6 +65,7 @@
 CONFIG_SF_DEFAULT_BUS=1
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SPI_FLASH_MTD=y
+CONFIG_PHY_ANEG_TIMEOUT=8000
 CONFIG_PHY_MARVELL=y
 CONFIG_PHY_GIGE=y
 CONFIG_MVNETA=y