Bluetooth: hci_bcm: checking for ERR_PTR instead of NULL

bt_skb_alloc() returns NULL on error, it never returns an ERR_PTR.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/hci_bcm.c

@@ -259,8 +259,8 @@ static int bcm_set_diag(struct hci_dev *hdev, bool enable)
 		return -ENETDOWN;
 
 	skb = bt_skb_alloc(3, GFP_KERNEL);
-	if (IS_ERR(skb))
-		return PTR_ERR(skb);
+	if (!skb)
+		return -ENOMEM;
 
 	*skb_put(skb, 1) = BCM_LM_DIAG_PKT;
 	*skb_put(skb, 1) = 0xf0;