Revert "Refactor Update operation to return amount of input consumed."

This reverts commit 125febcb5d1888fa82e8c2eb307513598a537999.
diff --git a/google_keymaster_messages.cpp b/google_keymaster_messages.cpp
index 3297a19..79e7e1b 100644
--- a/google_keymaster_messages.cpp
+++ b/google_keymaster_messages.cpp
@@ -188,16 +188,15 @@
 }
 
 size_t UpdateOperationResponse::NonErrorSerializedSize() const {
-    return output.SerializedSize() + sizeof(uint32_t);
+    return output.SerializedSize();
 }
 
 uint8_t* UpdateOperationResponse::NonErrorSerialize(uint8_t* buf, const uint8_t* end) const {
-    buf = output.Serialize(buf, end);
-    return append_uint32_to_buf(buf, end, input_consumed);
+    return output.Serialize(buf, end);
 }
 
 bool UpdateOperationResponse::NonErrorDeserialize(const uint8_t** buf_ptr, const uint8_t* end) {
-    return output.Deserialize(buf_ptr, end) && copy_uint32_from_buf(buf_ptr, end, &input_consumed);
+    return output.Deserialize(buf_ptr, end);
 }
 
 size_t FinishOperationRequest::SerializedSize() const {