usb: phy: don't return with NULL from devm_usb_get_phy()

The callers are expecting an ERR_PTR value in case
of an error. Change he code to return with an encoded
-ENOMEM value in the case of a failed devres_alloc call.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/phy/phy.c

@@ -98,7 +98,7 @@ struct usb_phy *devm_usb_get_phy(struct device *dev, enum usb_phy_type type)
 
 	ptr = devres_alloc(devm_usb_phy_release, sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	phy = usb_get_phy(type);
 	if (!IS_ERR(phy)) {