Remove an obsolete TODO

BUG=aomedia:2629

Change-Id: I47c5f6b7a87f5a718c7b7297294646a24ab27891

av1/common/av1_inv_txfm1d.c

diff --git a/av1/common/av1_inv_txfm1d.c b/av1/common/av1_inv_txfm1d.c
index 7ef2d6d..3d4e800 100644
--- a/av1/common/av1_inv_txfm1d.c
+++ b/av1/common/av1_inv_txfm1d.c
@@ -13,9 +13,6 @@
 #include "av1/common/av1_inv_txfm1d.h"
 #include "av1/common/av1_txfm.h"
 
-// TODO(angiebird): Make 1-d txfm functions static
-//
-
 void av1_idct4_new(const int32_t *input, int32_t *output, int8_t cos_bit,
                    const int8_t *stage_range) {
   assert(output != input);