usb: phy: fix return value check of usb_get_phy

usb_get_phy will return -ENODEV if it's not able to find the phy. Hence
fixed all the callers of usb_get_phy to check for this error condition
instead of relying on a non-zero value as success condition.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/power/isp1704_charger.c

@@ -416,7 +416,7 @@ static int __devinit isp1704_charger_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	isp->phy = usb_get_phy(USB_PHY_TYPE_USB2);
-	if (!isp->phy)
+	if (IS_ERR_OR_NULL(isp->phy))
 		goto fail0;
 
 	isp->dev = &pdev->dev;