ixgbe: fix bug with lots of tx queues

when using more than 8 tx queues you can overrun the 8 bit v_idx
field, so change it to 16 bits to represent the maximum number
of queues (one for each bit)
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/ixgbe/ixgbe.h

@@ -152,7 +152,7 @@ struct ixgbe_ring {
 	struct net_lro_mgr lro_mgr;
 	bool lro_used;
 	struct ixgbe_queue_stats stats;
-	u8 v_idx; /* maps directly to the index for this ring in the hardware
+	u16 v_idx; /* maps directly to the index for this ring in the hardware
 	           * vector array, can also be used for finding the bit in EICR
 	           * and friends that represents the vector for this ring */