idct.h: remove unused inclusions

Change-Id: I0a89e7eacf6941c735c9615af0bb74bc6d7d2ec4

av1/common/idct.h

diff --git a/av1/common/idct.h b/av1/common/idct.h
index 5045396..5beb57e 100644
--- a/av1/common/idct.h
+++ b/av1/common/idct.h
@@ -12,15 +12,12 @@
 #ifndef AV1_COMMON_IDCT_H_
 #define AV1_COMMON_IDCT_H_
 
-#include <assert.h>
-
 #include "./aom_config.h"
 #include "av1/common/blockd.h"
 #include "av1/common/common.h"
 #include "av1/common/enums.h"
 #include "aom_dsp/inv_txfm.h"
 #include "aom_dsp/txfm_common.h"
-#include "aom_ports/mem.h"
 
 #ifdef __cplusplus
 extern "C" {