Add missing function to telephony HIDL interface.

+ fix some comments as per specs.

Test: No test
Bug: 32020264
Change-Id: If8e83a7465e608e28f7e149025da5ede30924602
diff --git a/radio/1.0/IRadioResponse.hal b/radio/1.0/IRadioResponse.hal
index c49286b..e25a30c 100644
--- a/radio/1.0/IRadioResponse.hal
+++ b/radio/1.0/IRadioResponse.hal
@@ -1934,4 +1934,13 @@
      */
     oneway getAllowedCarriersResponse(RadioResponseInfo info, bool allAllowed,
             CarrierRestrictions carriers);
+
+    /*
+     * Acknowldege the receipt of radio request sent to the vendor. This must be sent only for
+     * radio request which take long time to respond.
+     * For more details, refer https://source.android.com/devices/tech/connect/ril.html
+     *
+     * @param serial Serial no. of the request whose acknowledgement is sent.
+     */
+    oneway requestAcknowledgement(int32_t serial);
 };