When rgmii-rxid/txid/id phy-mode is used the MAC should not add RX
and/or TX delay. Currently RX/TX delay is configured as enabled using
zero as delay value for the rgmii-rxid/txid/id modes.

Change to disable RX and/or TX delay and using zero as delay value.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>