cas: add flag for pes header descrambling

Change-Id: I5985a75cc5cbce2aea8d6068b3665572ed9e524c
diff --git a/headers/media_plugin/media/cas/DescramblerAPI.h b/headers/media_plugin/media/cas/DescramblerAPI.h
index 0a51952..033c8ce 100644
--- a/headers/media_plugin/media/cas/DescramblerAPI.h
+++ b/headers/media_plugin/media/cas/DescramblerAPI.h
@@ -48,6 +48,10 @@
         kScrambling_Reserved    = 1,
         kScrambling_EvenKey     = 2,
         kScrambling_OddKey      = 3,
+        kScrambling_Mask_Key    = 0x3,
+
+        // Hint that the descrambling request is for a PES header only
+        kScrambling_Flag_PesHeader = (1 << 31),
     };
 
     struct SubSample {