i40e: Fix a potential NULL pointer dereference

If 'kzalloc()' fails, a NULL pointer will be dereferenced.
Return an error code (-ENOMEM) instead.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c

@@ -423,6 +423,9 @@ static int i40e_config_iwarp_qvlist(struct i40e_vf *vf,
 	       (sizeof(struct virtchnl_iwarp_qv_info) *
 						(qvlist_info->num_vectors - 1));
 	vf->qvlist_info = kzalloc(size, GFP_KERNEL);
+	if (!vf->qvlist_info)
+		return -ENOMEM;
+
 	vf->qvlist_info->num_vectors = qvlist_info->num_vectors;
 
 	msix_vf = pf->hw.func_caps.num_msix_vectors_vf;