This patch makes the inet6_register_protosw to return an error code.
The different protocols can be aware the registration was successful or
not and can pass the error to the initial caller, af_inet6.
Signed-off-by: NDaniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>