avutil/mem_internal: Fix headers

Including avassert.h is unnecessary since commit
786be70e28.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/x86/h264_qpel.c

@@ -20,6 +20,7 @@
  */
 
 #include "libavutil/attributes.h"
+#include "libavutil/avassert.h"
 #include "libavutil/cpu.h"
 #include "libavutil/mem_internal.h"
 #include "libavutil/x86/asm.h"

libavutil/mem_internal.h

@@ -25,7 +25,8 @@
 
 #include <stdint.h>
 
-#include "avassert.h"
+#include "attributes.h"
+#include "macros.h"
 #include "mem.h"
 #include "version.h"
 

libavutil/tx.c

@@ -16,6 +16,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "avassert.h"
 #include "cpu.h"
 #include "qsort.h"
 #include "bprint.h"