iwlwifi: fix IDI compilation

This is a fixup for my:
iwlwifi: kill iwl_bus.h

Please fold them into one patch for upstream
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

drivers/net/wireless/iwlwifi/iwl-pci.c

@@ -278,7 +278,7 @@ static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 #ifdef CONFIG_IWLWIFI_IDI
 	iwl_trans = iwl_trans_idi_alloc(shrd, pdev, ent);
-	if (trans == NULL) {
+	if (iwl_trans == NULL) {
 		err = -ENOMEM;
 		goto out_free_bus;
 	}