net/ncsi: Don't return error on normal response

Several response handlers return EBUSY if the data corresponding to the
command/response pair is already set. There is no reason to return an
error here; the channel is advertising something as enabled because we
told it to enable it, and it's possible that the feature has been
enabled previously.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>