usb: phy: Fix deferred probing

Commit 1290a958 ("usb: phy: propagate __of_usb_find_phy()'s error on
failure") actually broke the deferred probing mechanism, since it now returns
EPROBE_DEFER only when the try_module_get call fails, but not when the phy
lookup does.

All the other similar functions seem to return ENODEV when try_module_get
fails, and the error code of either __usb_find_phy or __of_usb_find_phy
otherwise.

In order to have a consistent behaviour, and a meaningful EPROBE_DEFER, always
return EPROBE_DEFER when __(of_)usb_find_phy fails to look up the requested
phy, that will be propagated by the caller, and ENODEV if try_module_get fails.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>