netinet*: de-void control input IP protocol methods
After decoupling of protosw(9) and IP wire protocols in 78b1fc05b205 for
IPv4 we got vector ip_ctlprotox that is executed only and only from
icmp_input() and respectively for IPv6 we got ip6_ctlprotox executed
only and only from icmp6_input(). This allows to use protocol specific
argument types in these methods instead of struct sockaddr and void.
Reviewed by: melifaro
Differential revision: https://reviews.freebsd.org/D36727