lavc: Add missing #includes for ff_dlog()

libavcodec/ac3enc.c

@@ -42,6 +42,7 @@
 #include "ac3dsp.h"
 #include "ac3.h"
 #include "fft.h"
+#include "internal.h"
 #include "ac3enc.h"
 #include "eac3enc.h"
 

libavcodec/mpegaudiodecheader.c

@@ -27,6 +27,7 @@
 #include "libavutil/common.h"
 
 #include "avcodec.h"
+#include "internal.h"
 #include "mpegaudio.h"
 #include "mpegaudiodata.h"
 #include "mpegaudiodecheader.h"