cf-socket: Fix build when not HAVE_GETPEERNAME

Remove remaining references to conn and sockfd, which were removed from
the function signature when conninfo_remote was renamed to
conn_set_primary_ip in 6a8d7ef.

Closes https://github.com/curl/curl/pull/10343

lib/cf-socket.c

@@ -1174,8 +1174,6 @@ static void conn_set_primary_ip(struct Curl_cfilter *cf,
 #else
   cf->conn->primary_ip[0] = 0;
   (void)data;
-  (void)conn;
-  (void)sockfd;
 #endif
 }