Bluetooth: Add hci_skb_* helper wrappers for bt_cb(skb) access

For all the HCI driver related variables accesssed via bt_cb(skb),
provide helper wrappers.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

include/net/bluetooth/bluetooth.h

@@ -316,6 +316,10 @@ struct bt_skb_cb {
 };
 #define bt_cb(skb) ((struct bt_skb_cb *)((skb)->cb))
 
+#define hci_skb_pkt_type(skb) bt_cb((skb))->pkt_type
+#define hci_skb_expect(skb) bt_cb((skb))->expect
+#define hci_skb_opcode(skb) bt_cb((skb))->hci.opcode
+
 static inline struct sk_buff *bt_skb_alloc(unsigned int len, gfp_t how)
 {
 	struct sk_buff *skb;