ipg: per-device rxfrag_size

Add a ->max_rxframe member to struct ipg_nic_private and convert the users of
IPG_RXFRAG_SIZE to use it instead to enable per-device jumbo frame
configuration.

Tested-by: Andrew Savchenko <Bircoph@list.ru>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/ipg.h b/drivers/net/ipg.h
index 9c520ce..83e311e 100644
--- a/drivers/net/ipg.h
+++ b/drivers/net/ipg.h
@@ -796,6 +796,7 @@
 	unsigned int rx_dirty;
 	bool is_jumbo;
 	struct ipg_jumbo jumbo;
+	unsigned long rxfrag_size;
 	unsigned int rx_buf_sz;
 	struct pci_dev *pdev;
 	struct net_device *dev;