usb: core: Try generic PHY_MODE_USB_HOST if usb_phy_roothub_set_mode fails

Some PHYs do not support PHY_MODE_USB_HOST_SS, i.e. USB 3.0 or higher.
Fall back and try the more generic PHY_MODE_USB_HOST if it fails.

Fixes: b97a3134 ("usb: core: comply to PHY framework")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hcd.c

@@ -2741,6 +2741,9 @@ int usb_add_hcd(struct usb_hcd *hcd,
 
 		retval = usb_phy_roothub_set_mode(hcd->phy_roothub,
 						  PHY_MODE_USB_HOST_SS);
+		if (retval)
+			retval = usb_phy_roothub_set_mode(hcd->phy_roothub,
+							  PHY_MODE_USB_HOST);
 		if (retval)
 			goto err_usb_phy_roothub_power_on;