IB/hfi1: Fix potential NULL ptr dereference

This fixes potential NULL ptr dereference because IS_ERR(dd) doesn't
handle NULL. Fix the issue by initializing the pointer with a not NULL
error code.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/init.c

@@ -1383,7 +1383,7 @@ static void postinit_cleanup(struct hfi1_devdata *dd)
 static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	int ret = 0, j, pidx, initfail;
-	struct hfi1_devdata *dd = NULL;
+	struct hfi1_devdata *dd = ERR_PTR(-EINVAL);
 	struct hfi1_pportdata *ppd;
 
 	/* First, lock the non-writable module parameters */