net: add the AF_KCM entries to family name tables

This is for the recent kcm driver, which introduces AF_KCM(41) in
b7ac4eb(kcm: Kernel Connection Multiplexor module).

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>