socketutils: add const qualifier to variables

socketutils: add const qualifier to variables

* socketutils.c (cache_and_print_inode_details): Make "details"
parameter const.
(print_sockaddr_by_inode_cached): Make "e" variable const.
(inet_send_query): Make struct nlmsghdr and struct inet_diag_req_v2
members const.  Make "msg" variable const.
(inet_parse_response): Make "data" parameter and diag_msg variable const.
(receive_responses): Make "h" and "rc" variables const.
(unix_send_query): Make struct nlmsghdr and struct unix_diag_req
members const.  Make "msg" variable const.
(unix_print): Make all parameters const.
(print_sockaddr_by_inode): Make proto_name parameter const.