usb: Handle -ENODEV from usb_lowlevel_init()

As we support both Host and Device mode operation, an OTG controller
can return -ENODEV on a port which it found to be in Device mode during
Host mode scan for devices. In case -ENODEV is returned, print that the
port is not available and continue instead of screaming a bloody error
message.

Signed-off-by: Marek Vasut <marex@denx.de>