usb: phy: move some error messages to debug

the PHY layer is supposed to be optional,
considering some PHY have no control bus
for SW to poke around.

After commit 1ae5799e (usb: hcd: Initialize
USB phy if needed) any HCD which didn't provide
a PHY driver would emit annoying error messages.

In this patch we're decreasing those messages
to debugging only and we also add a PHY prefix
or use dev_dbg so we know where they're coming from.
Reported-by: NJosh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NJosh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/phy.c

@@ -130,7 +130,7 @@ struct usb_phy *usb_get_phy(enum usb_phy_type type)
 
 	phy = __usb_find_phy(&phy_list, type);
 	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
-		pr_err("unable to find transceiver of type %s\n",
+		pr_debug("PHY: unable to find transceiver of type %s\n",
 			usb_phy_type_string(type));
 		goto err0;
 	}
@@ -228,7 +228,7 @@ struct usb_phy *usb_get_phy_dev(struct device *dev, u8 index)
 
 	phy = __usb_find_phy_dev(dev, &phy_bind_list, index);
 	if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) {
-		pr_err("unable to find transceiver\n");
+		dev_dbg(dev, "unable to find transceiver\n");
 		goto err0;
 	}
 
@@ -424,10 +424,8 @@ int usb_bind_phy(const char *dev_name, u8 index,
 	unsigned long flags;
 
 	phy_bind = kzalloc(sizeof(*phy_bind), GFP_KERNEL);
-	if (!phy_bind) {
-		pr_err("phy_bind(): No memory for phy_bind");
+	if (!phy_bind)
 		return -ENOMEM;
-	}
 
 	phy_bind->dev_name = dev_name;
 	phy_bind->phy_dev_name = phy_dev_name;