stmmac: dwmac-socfpga: fix wrong pointer passed to PTR_ERR()

PTR_ERR should access the value just tested by IS_ERR, otherwise
the wrong error code will be returned.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c

@@ -214,7 +214,7 @@ static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *
 				dev_err(dev,
 					"%s: ERROR: failed mapping tse control port\n",
 					__func__);
-				return PTR_ERR(dwmac->pcs.sgmii_adapter_base);
+				return PTR_ERR(dwmac->pcs.tse_pcs_base);
 			}
 		}
 	}