net: thunderx: use proper interface type for RGMII

The configuration of the OCTEONTX XCV_DLL_CTL register via
xcv_init_hw() is such that the RGMII RX delay is bypassed
leaving the RGMII TX delay enabled in the MAC:

	/* Configure DLL - enable or bypass
	 * TX no bypass, RX bypass
	 */
	cfg = readq_relaxed(xcv->reg_base + XCV_DLL_CTL);
	cfg &= ~0xFF03;
	cfg |= CLKRX_BYP;
	writeq_relaxed(cfg, xcv->reg_base + XCV_DLL_CTL);

This would coorespond to a interface type of PHY_INTERFACE_MODE_RGMII_RXID
and not PHY_INTERFACE_MODE_RGMII.

Fixing this allows RGMII PHY drivers to do the right thing (enable
RX delay in the PHY) instead of erroneously enabling both delays in the
PHY.
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cavium/thunder/thunder_bgx.c

@@ -1039,7 +1039,7 @@ static int phy_interface_mode(u8 lmac_type)
 	if (lmac_type == BGX_MODE_QSGMII)
 		return PHY_INTERFACE_MODE_QSGMII;
 	if (lmac_type == BGX_MODE_RGMII)
-		return PHY_INTERFACE_MODE_RGMII;
+		return PHY_INTERFACE_MODE_RGMII_RXID;
 
 	return PHY_INTERFACE_MODE_SGMII;
 }