ixgbevf: set the disable state when ixgbevf_qv_disable is called

The ixgbevf_qv_disable function used by CONFIG_NET_RX_BUSY_POLL is broken,
because it does not properly set the IXGBEVF_QV_STATE_DISABLED bit, indicating
that the q_vector should be disabled (and preventing future locks from
obtaining the vector). This patch corrects the issue by setting the disable
state.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbevf/ixgbevf.h

@@ -260,6 +260,7 @@ static inline bool ixgbevf_qv_disable(struct ixgbevf_q_vector *q_vector)
 	spin_lock_bh(&q_vector->lock);
 	if (q_vector->state & IXGBEVF_QV_OWNED)
 		rc = false;
+	q_vector->state |= IXGBEVF_QV_STATE_DISABLED;
 	spin_unlock_bh(&q_vector->lock);
 	return rc;
 }