Mark IMS_NULL as deprecated.

Bug: b/328449089
Test: m
Change-Id: I23610bd5736310ebbe6c78271343c5db48425a1a
diff --git a/radio/aidl/android/hardware/radio/network/SecurityAlgorithm.aidl b/radio/aidl/android/hardware/radio/network/SecurityAlgorithm.aidl
index 01f7327..451eaa9 100644
--- a/radio/aidl/android/hardware/radio/network/SecurityAlgorithm.aidl
+++ b/radio/aidl/android/hardware/radio/network/SecurityAlgorithm.aidl
@@ -62,7 +62,7 @@
     // IMS and SIP layer security (See 3GPP TS 33.203)
     // No IPsec config
     SIP_NO_IPSEC_CONFIG = 66,
-    IMS_NULL = 67,
+    IMS_NULL = 67, // Deprecated. Use SIP_NO_IPSEC_CONFIG and SIP_NULL instead.
 
     // Has IPsec config
     SIP_NULL = 68,