ibmvnic: Introduce driver limits for ring sizes

Introduce driver-defined maximums for queue ring sizes. Devices
available for IBM vNIC today will likely not allow this amount,
but this should give us some leeway for future devices that may
support larger ring sizes.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmvnic.h

@@ -40,6 +40,7 @@
 /* when changing this, update IBMVNIC_IO_ENTITLEMENT_DEFAULT */
 #define IBMVNIC_BUFFS_PER_POOL	100
 #define IBMVNIC_MAX_QUEUES	16
+#define IBMVNIC_MAX_QUEUE_SZ   4096
 
 #define IBMVNIC_TSO_BUF_SZ	65536
 #define IBMVNIC_TSO_BUFS	64