Fix clang -Werror from unused parameters.

Change-Id: I4fc080bc6671bf415fbef2d27e5c35e0072b2644
diff --git a/include/keyguard/keyguard_messages.h b/include/keyguard/keyguard_messages.h
index 9907527..42ba826 100644
--- a/include/keyguard/keyguard_messages.h
+++ b/include/keyguard/keyguard_messages.h
@@ -43,9 +43,10 @@
     keyguard_error_t GetError() const { return error_; }
 
 protected:
-    virtual size_t nonErrorSerializedSize() const { return 0; } ;
-    virtual void nonErrorSerialize(uint8_t *buffer) const { }
-    virtual keyguard_error_t nonErrorDeserialize(const uint8_t *payload, const uint8_t *end) {
+    virtual size_t nonErrorSerializedSize() const { return 0; }
+    virtual void nonErrorSerialize(uint8_t * /* buffer */) const { }
+    virtual keyguard_error_t nonErrorDeserialize(const uint8_t * /* payload */,
+                                                 const uint8_t * /* end */) {
         return KG_ERROR_OK;
     }