stmmac: devm_reset_control_get can return PROBE_DEFER

In socfpga_dwmac_parse_data forward error code from devm_reset_control_get.
This gives the driver another chance to laod if altr,rst-mgr is loaded after
the network driver.
Signed-off-by: NPhil Reid <preid@electromag.com.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -91,7 +91,7 @@ static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *
 						  STMMAC_RESOURCE_NAME);
 	if (IS_ERR(dwmac->stmmac_rst)) {
 		dev_info(dev, "Could not get reset control!\n");
-		return -EINVAL;
+		return PTR_ERR(dwmac->stmmac_rst);
 	}
 
 	dwmac->interface = of_get_phy_mode(np);