rxrpc: Increase the size of a call's Rx window

Increase the size of a call's Rx window from 32 to 63 - ie. one less than
the size of the ring buffer.  This makes large data transfers perform
better when the Tx window on the other side is around 64 (as is the case
with Auristor's YFS fileserver).

If the server window size is ~32 or smaller, this should make no
difference.
Signed-off-by: David Howells <dhowells@redhat.com>

net/rxrpc/ar-internal.h

@@ -589,7 +589,7 @@ struct rxrpc_call {
 	 */
 #define RXRPC_RXTX_BUFF_SIZE	64
 #define RXRPC_RXTX_BUFF_MASK	(RXRPC_RXTX_BUFF_SIZE - 1)
-#define RXRPC_INIT_RX_WINDOW_SIZE 32
+#define RXRPC_INIT_RX_WINDOW_SIZE 63
 	struct sk_buff		**rxtx_buffer;
 	u8			*rxtx_annotations;
 #define RXRPC_TX_ANNO_ACK	0