net: dwmac_meson8b: do not set TX delay in TXID & RXID

When the PHY interface is set as TXID & RXID, the delays should be taken from DT,
but first they should not be hardcoded since the PHY driver will set them.

Fixes: 798424e8 ("net: designware: add Amlogic Meson8b & later glue driver")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>