lantiq: drop phy id specfic compatible string

lantiq: drop phy id specfic compatible string

With kernel commit 7630ea4bda18 ("Documentation: net: phy: improve
explanation when to specify the PHY ID") the purpose of using phy id
specific compatibles was clarified.

Remove the phy id specific compatibles since they are meant to be used
if the phy reports an incorrect or no phy id at all.

Reported-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Mathias Kresin <dev@kresin.me>