[Bluetooth] Add constant for Bluetooth socket options level

Assign the next free socket options level to be used by the Bluetooth
protocol and address family.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/linux/socket.h

@@ -291,6 +291,7 @@ struct ucred {
 #define SOL_TIPC	271
 #define SOL_RXRPC	272
 #define SOL_PPPOL2TP	273
+#define SOL_BLUETOOTH	274
 
 /* IPX options */
 #define IPX_TYPE	1