net: designware: socfpga: Add RGMII-ID support

This patch adds support for the "rgmii-id", "rgmii-rxid", and
"rgmii-txid" modes for the dwmac_socfpga driver.

Signed-off-by: Rufus Segar <rhs@riseup.net>
diff --git a/drivers/net/dwmac_socfpga.c b/drivers/net/dwmac_socfpga.c
index a9e2d8c..a55f3e2 100644
--- a/drivers/net/dwmac_socfpga.c
+++ b/drivers/net/dwmac_socfpga.c
@@ -106,6 +106,9 @@
 		modereg = SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RMII;
 		break;
 	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
 		modereg = SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RGMII;
 		break;
 	default: