usb: phy: propagate __of_usb_find_phy()'s error on failure

When __of_usb_find_phy() fails, it returns -ENODEV - its
error code has to be returned by devm_usb_get_phy_by_phandle().
Only when the former function succeeds and try_module_get()
fails should -EPROBE_DEFER be returned.

[ balbi@ti.com : remove trailing whitespace ]

Signed-off-by: Arjun Sreedharan <arjun024@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>