i40e/i40evf: save aq writeback for future inspection

Add the ability to save the AdminQ write back descriptor if a
caller supplies a buffer for it to be saved into.

Change-ID: I3d1301d26360b39a2d66dc8569e851f54133a3af
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_adminq.h b/drivers/net/ethernet/intel/i40evf/i40e_adminq.h
index ef43d68..547b79b 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_adminq.h
+++ b/drivers/net/ethernet/intel/i40evf/i40e_adminq.h
@@ -69,6 +69,7 @@
 	u16 flags_dis;
 	bool async;
 	bool postpone;
+	struct i40e_aq_desc *wb_desc;
 };
 
 #define I40E_ADMINQ_DETAILS(R, i)   \