AHAL: update doc for prepareToDisconnectExternalDevice.

Bug: 317405349
Test: make
Change-Id: If6c61a851c2e565ab16eb738b9dc0d42ebc04b05
diff --git a/audio/aidl/android/hardware/audio/core/IModule.aidl b/audio/aidl/android/hardware/audio/core/IModule.aidl
index 2d4d283..3c5f7f6 100644
--- a/audio/aidl/android/hardware/audio/core/IModule.aidl
+++ b/audio/aidl/android/hardware/audio/core/IModule.aidl
@@ -928,7 +928,10 @@
      * using 'connectExternalDevice' method. 'disconnectExternalDevice' method will be called
      * soon after this method with the same 'portId'.
      *
-     * @param portId The ID of the audio port that is about to disconnect
+     * Note: This method is called after the external device is disconnected. The system does
+     * not try to predict the disconnection event.
+     *
+     * @param portId The ID of the audio port corresponding to the disconnected device
      * @throws EX_ILLEGAL_ARGUMENT In the following cases:
      *                             - If the port can not be found by the ID.
      *                             - If this is not a connected device port.