lavc: use avpriv_ prefix for ff_copy_bits and align_put_bits.

They are used in lavf.

libavcodec/h261enc.c

@@ -53,7 +53,7 @@ void ff_h261_encode_picture_header(MpegEncContext * s, int picture_number){
     H261Context * h = (H261Context *) s;
     int format, temp_ref;
 
-    align_put_bits(&s->pb);
+    avpriv_align_put_bits(&s->pb);
 
     /* Update the pointer to last GOB */
     s->ptr_lastgob = put_bits_ptr(&s->pb);