Move daala_fdct64() / daala_idct64() into daala_tx.c.

This commit has no impact on metrics.

Change-Id: I29e927e64938a5a88bf6b359774f92719df2a4af
diff --git a/av1/common/daala_tx.c b/av1/common/daala_tx.c
index 834682e..5ae7df0 100644
--- a/av1/common/daala_tx.c
+++ b/av1/common/daala_tx.c
@@ -4232,3 +4232,23 @@
   od_bin_idct32(x, 1, y);
   for (i = 0; i < 32; i++) output[i] = (tran_low_t)x[i];
 }
+
+#if CONFIG_TX64X64
+void daala_fdct64(const tran_low_t *input, tran_low_t *output) {
+  int i;
+  od_coeff x[64];
+  od_coeff y[64];
+  for (i = 0; i < 64; i++) x[i] = (od_coeff)input[i];
+  od_bin_fdct64(y, x, 1);
+  for (i = 0; i < 64; i++) output[i] = (tran_low_t)y[i];
+}
+
+void daala_idct64(const tran_low_t *input, tran_low_t *output) {
+  int i;
+  od_coeff x[64];
+  od_coeff y[64];
+  for (i = 0; i < 64; i++) y[i] = (od_coeff)input[i];
+  od_bin_idct64(x, 1, y);
+  for (i = 0; i < 64; i++) output[i] = (tran_low_t)x[i];
+}
+#endif