Bluetooth: Add skeleton for SMP self-tests

This patch adds the initial skeleton and kernel config option for SMP
self-tests.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/net/bluetooth/smp.h b/net/bluetooth/smp.h
index 3296bf4..60c5b73 100644
--- a/net/bluetooth/smp.h
+++ b/net/bluetooth/smp.h
@@ -192,4 +192,17 @@
 int smp_register(struct hci_dev *hdev);
 void smp_unregister(struct hci_dev *hdev);
 
+#if IS_ENABLED(CONFIG_BT_SELFTEST_SMP)
+
+int bt_selftest_smp(void);
+
+#else
+
+static inline int bt_selftest_smp(void)
+{
+	return 0;
+}
+
+#endif
+
 #endif /* __SMP_H */