lavc/h264_parse: stop including h264dec.h

It is unnecessary and only files that are parts of the decoder (as
opposed to standalone code called by the decoder) are allowed to include
h264dec.h

libavcodec/h264_parse.c

@@ -20,9 +20,11 @@
 #include "get_bits.h"
 #include "golomb.h"
 #include "h264.h"
-#include "h264dec.h"
+#include "h264pred.h"
 #include "h264_parse.h"
 #include "h264_ps.h"
+#include "h2645_parse.h"
+#include "mpegutils.h"
 
 int ff_h264_pred_weight_table(GetBitContext *gb, const SPS *sps,
                               const int *ref_count, int slice_type_nos,