Add deprecation warning to IMS_REGISTRATION RIL Calls

-Deprecation warning for RIL_REQUEST_IMS_REGISTRATION_STATE
-Deprecation warning for RIL_UNSOL_RESPONSE_IMS_NETWORK_STATE_CHANGED

Bug: 33750436
Test: complation
Change-Id: Ieb7c2fc5061998e4d04a9d044cf3d883d01e995d
diff --git a/include/telephony/ril.h b/include/telephony/ril.h
index 0cadea5..730c047 100644
--- a/include/telephony/ril.h
+++ b/include/telephony/ril.h
@@ -4667,6 +4667,9 @@
 /**
  * RIL_REQUEST_IMS_REGISTRATION_STATE
  *
+ * This message is DEPRECATED and shall be removed in a future release (target: 2018);
+ * instead, provide IMS registration status via an IMS Service.
+ *
  * Request current IMS registration state
  *
  * "data" is NULL
@@ -5677,6 +5680,9 @@
 /**
  * RIL_UNSOL_RESPONSE_IMS_NETWORK_STATE_CHANGED
  *
+ * This message is DEPRECATED and shall be removed in a future release (target: 2018);
+ * instead, provide IMS registration status via an IMS Service.
+ *
  * Called when IMS registration state has changed
  *
  * To get IMS registration state and IMS SMS format, callee needs to invoke the