arm64: imx8mp: Disable Atheros PHY driver on i.MX8MP DHCOM

These SoMs never ship with Atheros PHYs, disable the Atheros PHY driver.

Signed-off-by: Marek Vasut <marex@denx.de>
diff --git a/configs/imx8mp_dhcom_pdk2_defconfig b/configs/imx8mp_dhcom_pdk2_defconfig
index ecc28c8..fc72df9 100644
--- a/configs/imx8mp_dhcom_pdk2_defconfig
+++ b/configs/imx8mp_dhcom_pdk2_defconfig
@@ -196,7 +196,6 @@
 # CONFIG_SPI_FLASH_UNLOCK_ALL is not set
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_SPI_FLASH_MTD=y
-CONFIG_PHY_ATHEROS=y
 CONFIG_PHY_MICREL=y
 CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_DM_MDIO=y