fm10k: reduce scope of the ring variable

Reduce the scope of the ring local variable in the fm10k_assign_l2_accel
function.

This was detected by cppcheck and resolves the following warning
produced by that tool:

[fm10k_netdev.c:1447]: (style) The scope of the variable 'ring' can be
reduced.
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/fm10k/fm10k_netdev.c

@@ -1444,11 +1444,11 @@ static int __fm10k_setup_tc(struct net_device *dev, enum tc_setup_type type,
 static void fm10k_assign_l2_accel(struct fm10k_intfc *interface,
 				  struct fm10k_l2_accel *l2_accel)
 {
-	struct fm10k_ring *ring;
 	int i;
 
 	for (i = 0; i < interface->num_rx_queues; i++) {
-		ring = interface->rx_ring[i];
+		struct fm10k_ring *ring = interface->rx_ring[i];
+
 		rcu_assign_pointer(ring->l2_accel, l2_accel);
 	}