rtpdec: Remove the now unused .alloc field

Always use the .priv_data_size field instead.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/rtpdec.h

@@ -127,8 +127,6 @@ struct RTPDynamicProtocolHandler {
     /** Parse the a= line from the sdp field */
     int (*parse_sdp_a_line)(AVFormatContext *s, int st_index,
                             PayloadContext *priv_data, const char *line);
-    /** Allocate any data needed by the rtp parsing for this dynamic data. */
-    PayloadContext *(*alloc)(void);
     /** Free any data needed by the rtp parsing for this dynamic data. */
     void (*free)(PayloadContext *protocol_data);
     /** Parse handler for this dynamic packet */

libavformat/rtsp.c

@@ -186,11 +186,7 @@ static void init_rtp_handler(RTPDynamicProtocolHandler *handler,
     rtsp_st->dynamic_handler = handler;
     if (st)
         st->need_parsing = handler->need_parsing;
-    if (handler->alloc) {
-        rtsp_st->dynamic_protocol_context = handler->alloc();
-        if (!rtsp_st->dynamic_protocol_context)
-            rtsp_st->dynamic_handler = NULL;
-    } else if (handler->priv_data_size) {
+    if (handler->priv_data_size) {
         rtsp_st->dynamic_protocol_context = av_mallocz(handler->priv_data_size);
         if (!rtsp_st->dynamic_protocol_context)
             rtsp_st->dynamic_handler = NULL;