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/r8a779h0_grayhawk_defconfig b/configs/r8a779h0_grayhawk_defconfig
index a986a09..6cbe27a 100644
--- a/configs/r8a779h0_grayhawk_defconfig
+++ b/configs/r8a779h0_grayhawk_defconfig
@@ -60,6 +60,7 @@
 # CONFIG_SPI_FLASH_USE_4K_SECTORS is not set
 CONFIG_BITBANGMII=y
 CONFIG_BITBANGMII_MULTI=y
+CONFIG_PHY_ANEG_TIMEOUT=20000
 CONFIG_PHY_MICREL=y
 CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_DM_ETH_PHY=y