Add guest mode functionality (3/4)

Add a flag to enable() to start Bluetooth in restricted
mode. In restricted mode, all devices that are paired during
restricted mode are deleted upon leaving restricted mode.
Right now restricted mode is only entered while a guest
user is active

Bug: 27410683
Change-Id: Ibededbdb832275db4b6e78af83d26754f8b5a9ec

include/hardware/bluetooth.h

@@ -463,7 +463,7 @@ typedef struct {
     int (*init)(bt_callbacks_t* callbacks );
 
     /** Enable Bluetooth. */
-    int (*enable)(void);
+    int (*enable)(bool guest_mode);
 
     /** Disable Bluetooth. */
     int (*disable)(void);