MINOR: quic: remove unused xprt rcv_buf operation

rcv_buf and the implement quic_conn_to_buf is not used. recvfrom instead
is called on the listener polling task via quic_sock_fd_iocb.
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index eee9bae..7ad4382 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -5143,61 +5143,6 @@
 	return NULL;
 }
 
-/* Copy up to <count> bytes from connection <conn> internal stream storage into buffer <buf>.
- * Return the number of bytes which have been copied.
- */
-static size_t quic_conn_to_buf(struct connection *conn, void *xprt_ctx,
-                               struct buffer *buf, size_t count, int flags)
-{
-	size_t try, done = 0;
-
-	if (!conn_ctrl_ready(conn))
-		return 0;
-
-	if (!fd_recv_ready(conn->handle.fd))
-		return 0;
-
-	conn->flags &= ~CO_FL_WAIT_ROOM;
-
-	/* read the largest possible block. For this, we perform only one call
-	 * to recv() unless the buffer wraps and we exactly fill the first hunk,
-	 * in which case we accept to do it once again.
-	 */
-	while (count > 0) {
-		try = b_contig_space(buf);
-		if (!try)
-			break;
-
-		if (try > count)
-			try = count;
-
-		b_add(buf, try);
-		done += try;
-		count -= try;
-	}
-
-	if (unlikely(conn->flags & CO_FL_WAIT_L4_CONN) && done)
-		conn->flags &= ~CO_FL_WAIT_L4_CONN;
-
- leave:
-	return done;
-
- read0:
-	conn_sock_read0(conn);
-	conn->flags &= ~CO_FL_WAIT_L4_CONN;
-
-	/* Now a final check for a possible asynchronous low-level error
-	 * report. This can happen when a connection receives a reset
-	 * after a shutdown, both POLL_HUP and POLL_ERR are queued, and
-	 * we might have come from there by just checking POLL_HUP instead
-	 * of recv()'s return value 0, so we have no way to tell there was
-	 * an error without checking.
-	 */
-	if (unlikely(fdtab[conn->handle.fd].state & FD_POLL_ERR))
-		conn->flags |= CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH;
-	goto leave;
-}
-
 
 /* Send up to <count> pending bytes from buffer <buf> to connection <conn>'s
  * socket. <flags> may contain some CO_SFL_* flags to hint the system about
@@ -5337,7 +5282,6 @@
 static struct xprt_ops ssl_quic = {
 	.close    = quic_close,
 	.snd_buf  = quic_conn_from_buf,
-	.rcv_buf  = quic_conn_to_buf,
 	.subscribe = quic_conn_subscribe,
 	.unsubscribe = quic_conn_unsubscribe,
 	.init     = qc_conn_init,