The commit backporting new MTK patches did not update the
Kernel config for mediatek/mt7622 causing the build to
fail.
Simply use the new config symbol name for the driver to
fix the issue.
Fixes: 1069514978 ("mediatek: backport pending Ethernet PHY driver patches")
Signed-off-by: Rany Hany <rany_hany@riseup.net>
Link: https://github.com/openwrt/openwrt/pull/16225
Signed-off-by: Robert Marko <robimarko@gmail.com>