fdct8x8_test:: quiet unused-function warning

in non-x86 builds

Change-Id: I9f6fa40d27f95a4afe92444f71c23dc9a15db466

test/fdct8x8_test.cc

@@ -107,6 +107,8 @@ void iht8x8_12(const tran_low_t *in, uint8_t *out, int stride, int tx_type) {
   vp9_highbd_iht8x8_64_add_c(in, out, stride, tx_type, 12);
 }
 
+#if HAVE_SSE2
+
 void idct8x8_10_add_10_c(const tran_low_t *in, uint8_t *out, int stride) {
   vpx_highbd_idct8x8_10_add_c(in, out, stride, 10);
 }
@@ -115,7 +117,6 @@ void idct8x8_10_add_12_c(const tran_low_t *in, uint8_t *out, int stride) {
   vpx_highbd_idct8x8_10_add_c(in, out, stride, 12);
 }
 
-#if HAVE_SSE2
 void idct8x8_10_add_10_sse2(const tran_low_t *in, uint8_t *out, int stride) {
   vpx_highbd_idct8x8_10_add_sse2(in, out, stride, 10);
 }