UPSTREAM: net: stmmac: dwmac-rk: Add handling for RGMII_ID/RXID/TXID

UPSTREAM: net: stmmac: dwmac-rk: Add handling for RGMII_ID/RXID/TXID

ATM dwmac-rk will always set and enable it's internal delay lines.
Using PHY internal delays in combination with the phy-mode
rgmii-id/rxid/txid was not possible. Only rgmii was supported.

Now we can disable rockchip's gmac delay lines and also use
rgmii-id/rxid/txid.

Tested only with a RK3288 based board.

Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit eaf70ad14cbbb99d46b78b1307628a16a3f6075d)
Change-Id: Id0152a9f048cbc810b62c252d4105594ed1895df
Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>