net: phy: dp83867: Set up RGMII TX delay

PHY_INTERFACE_MODE_RGMII_RXID is less then TXID
so code to set tx delay is never called.

Fixes: 2a10154a ("net: phy: dp83867: Add TI dp83867 phy")
Signed-off-by: Max Uvarov <muvarov@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>