When host capabilities check failed or when we were unable to register doorbell
bitmap we were forgetting to set error code and were returning 0 which would
make upper layers believe that probe was successful.
Reported-by: NJulia Lawall <julia.lawall@lip6.fr>
Acked-by: NAndy King <acking@vmware.com>
Signed-off-by: NDmitry Torokhov <dtor@vmware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>