socket: remove redundant call to getsockname

The result "add" is unused.

Closes #13655

lib/cf-socket.c

@@ -616,16 +616,6 @@ static CURLcode bindlocal(struct Curl_easy *data, struct connectdata *conn,
   for(;;) {
     if(bind(sockfd, sock, sizeof_sa) >= 0) {
       /* we succeeded to bind */
-      struct Curl_sockaddr_storage add;
-      curl_socklen_t size = sizeof(add);
-      memset(&add, 0, sizeof(struct Curl_sockaddr_storage));
-      if(getsockname(sockfd, (struct sockaddr *) &add, &size) < 0) {
-        char buffer[STRERROR_LEN];
-        data->state.os_errno = error = SOCKERRNO;
-        failf(data, "getsockname() failed with errno %d: %s",
-              error, Curl_strerror(error, buffer, sizeof(buffer)));
-        return CURLE_INTERFACE_FAILED;
-      }
       infof(data, "Local port: %hu", port);
       conn->bits.bound = TRUE;
       return CURLE_OK;