fdct8x8_test.cc: remove unused param warnings

Change-Id: Ic53cdb8c9f8312e7404505fcec653d5b9e9587d1

test/fdct8x8_test.cc

diff --git a/test/fdct8x8_test.cc b/test/fdct8x8_test.cc
index 567e5f6..a694f0c 100644
--- a/test/fdct8x8_test.cc
+++ b/test/fdct8x8_test.cc
@@ -39,7 +39,7 @@
 typedef std::tr1::tuple<FdctFunc, IdctFunc, int> Dct8x8Param;
 typedef std::tr1::tuple<FhtFunc, IhtFunc, int> Ht8x8Param;
 
-void fdct8x8_ref(const int16_t *in, int16_t *out, int stride, int tx_type) {
+void fdct8x8_ref(const int16_t *in, int16_t *out, int stride, int /*tx_type*/) {
   vp9_fdct8x8_c(in, out, stride);
 }