[Bluetooth] Track status of remote Simple Pairing mode

The Simple Pairing process can only be used if both sides have the
support enabled in the host stack. The current Bluetooth specification
has three ways to detect this support.

If an Extended Inquiry Result has been sent during inquiry then it
is safe to assume that Simple Pairing is enabled. It is not allowed
to enable Extended Inquiry without Simple Pairing. During the remote
name request phase a notification with the remote host supported
features will be sent to indicate Simple Pairing support. Also the
second page of the remote extended features can indicate support for
Simple Pairing.

For all three cases the value of remote Simple Pairing mode is stored
in the inquiry cache for later use.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 6d0c04a..5ac0a18 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -816,6 +816,12 @@
 	bdaddr_t bdaddr;
 } __attribute__ ((packed));
 
+#define HCI_EV_REMOTE_HOST_FEATURES	0x3d
+struct hci_ev_remote_host_features {
+	bdaddr_t bdaddr;
+	__u8     features[8];
+} __attribute__ ((packed));
+
 /* Internal events generated by Bluetooth stack */
 #define HCI_EV_STACK_INTERNAL	0xfd
 struct hci_ev_stack_internal {