usb: ehci-omap: Fix deferred probe for phy handling

PHY model is being used on omap5 platforms even if port mode
is not OMAP_EHCI_PORT_MODE_PHY. So don't guess if PHY is required
or not based on PHY mode.

If PHY is provided in device tree, it must be required. So, if
devm_usb_get_phy_by_phandle() gives us an error code other
than -ENODEV (no PHY) then error out.

This fixes USB Ethernet on omap5-uevm if PHY happens to
probe after EHCI thus causing a -EPROBE_DEFER.

Cc: Johan Hovold <[e-mail]>
Cc: Ladislav Michl <[e-mail]>
Reported-by: Peter Ujfalusi <[e-mail]>
Signed-off-by: Roger Quadros <[e-mail]>
Tested-by: Peter Ujfalusi <[e-mail]>
Acked-by: Tony Lindgren <[e-mail]>
Acked-by: Alan Stern <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/ehci-omap.c

···
 		/* get the PHY device */
 		phy = devm_usb_get_phy_by_phandle(dev, "phys", i);
 		if (IS_ERR(phy)) {
-			/* Don't bail out if PHY is not absolutely necessary */
-			if (pdata->port_mode[i] != OMAP_EHCI_PORT_MODE_PHY)
-				continue;
-
 			ret = PTR_ERR(phy);
+			if (ret == -ENODEV) { /* no PHY */
+				phy = NULL;
+				continue;
+			}
+
 			if (ret != -EPROBE_DEFER)
 				dev_err(dev, "Can't get PHY for port %d: %d\n",
 					i, ret);