Update comment for the INonStandardCertCallback to
indicate how certificates are added.

Bug: 267819850
Test: m
Change-Id: I896bf68138b93a97c843699d69bac193e7ee1523
diff --git a/wifi/supplicant/aidl/android/hardware/wifi/supplicant/INonStandardCertCallback.aidl b/wifi/supplicant/aidl/android/hardware/wifi/supplicant/INonStandardCertCallback.aidl
index 2f9e528..2e11c76 100644
--- a/wifi/supplicant/aidl/android/hardware/wifi/supplicant/INonStandardCertCallback.aidl
+++ b/wifi/supplicant/aidl/android/hardware/wifi/supplicant/INonStandardCertCallback.aidl
@@ -18,7 +18,8 @@
 
 /**
  * Callback to allow supplicant to retrieve non-standard certificate types
- * from the client.
+ * from the framework. Certificates can be stored in the framework using
+ * the WifiKeystore#put system API.
  *
  * Must be registered by the client at initialization, so that
  * supplicant can call into the client to retrieve any values.