usb: phy: tegra: Fix unnecessary check in tegra_usb_phy_probe()

In the function tegra_usb_phy_probe(), if usb_add_phy_dev() failed,
the return value will be given to err, and if usb_add_phy_dev() succeed,
the return value will be zero. Thus it is unnecessary to repeated check
here.
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/phy/phy-tegra-usb.c

@@ -1199,11 +1199,7 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, tegra_phy);
 
-	err = usb_add_phy_dev(&tegra_phy->u_phy);
-	if (err)
-		return err;
-
-	return 0;
+	return usb_add_phy_dev(&tegra_phy->u_phy);
 }
 
 static int tegra_usb_phy_remove(struct platform_device *pdev)