ixgbe: Initialize q_vector cpu and affinity masks correctly

When enabling DCB the rings belonging to a q_vector on CPU 0 were not
reinitializing their DCA registers.  Upon closer inspection the issue was
that the q_vector CPU variable was left at 0 resulting in the driver not
updating the DCA registers.

In order to guarantee the DCA registers will be updated I am adding a
couple line change so that we initialize the CPU variable to -1 which will
force a DCA update the first time an interrupt fires on that q_vector.

In addition we were setting the CPU affinity hint to all CPUs when we were
not specifying a CPU.  Instead we should leave it as all zeros to avoid any
possible confusion about the fact that we shouldn't be giving a hint.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c

@@ -802,10 +802,13 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 	/* setup affinity mask and node */
 	if (cpu != -1)
 		cpumask_set_cpu(cpu, &q_vector->affinity_mask);
-	else
-		cpumask_copy(&q_vector->affinity_mask, cpu_online_mask);
 	q_vector->numa_node = node;
 
+#ifdef CONFIG_IXGBE_DCA
+	/* initialize CPU for DCA */
+	q_vector->cpu = -1;
+
+#endif
 	/* initialize NAPI */
 	netif_napi_add(adapter->netdev, &q_vector->napi,
 		       ixgbe_poll, 64);