llc/snap: constify dev_addr passing

In preparation for netdev->dev_addr being constant
make all relevant arguments in LLC and SNAP constant.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/datalink.h

@@ -12,7 +12,7 @@ struct datalink_proto {
         int     (*rcvfunc)(struct sk_buff *, struct net_device *,
                                 struct packet_type *, struct net_device *);
 	int     (*request)(struct datalink_proto *, struct sk_buff *,
-                                        unsigned char *);
+			   const unsigned char *);
 	struct list_head node;
 };
 

include/net/llc.h

@@ -133,7 +133,7 @@ static inline void llc_sap_put(struct llc_sap *sap)
 struct llc_sap *llc_sap_find(unsigned char sap_value);
 
 int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
-			      unsigned char *dmac, unsigned char dsap);
+			      const unsigned char *dmac, unsigned char dsap);
 
 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb);
 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb);

include/net/llc_if.h

@@ -62,7 +62,8 @@
 #define LLC_STATUS_CONFLICT	7 /* disconnect conn */
 #define LLC_STATUS_RESET_DONE	8 /*  */
 
-int llc_establish_connection(struct sock *sk, u8 *lmac, u8 *dmac, u8 dsap);
+int llc_establish_connection(struct sock *sk, const u8 *lmac, u8 *dmac,
+			     u8 dsap);
 int llc_build_and_send_pkt(struct sock *sk, struct sk_buff *skb);
 int llc_send_disc(struct sock *sk);
 #endif /* LLC_IF_H */