There was not any kind of protection against carrier driver removal.
In this way, device driver can 'get' the carrier driver when it is
using it.
Signed-off-by: Federico Vaga <federico.vaga@cern.ch>
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>