Doxygenize the unaltered comments for the RTP_MAX_SDES definition.

Originally committed as revision 8247 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtp.h

@@ -55,7 +55,7 @@ extern URLProtocol rtp_protocol;
 
 #define RTP_PT_PRIVATE 96
 #define RTP_VERSION 2
-#define RTP_MAX_SDES 256   /* maximum text length for SDES */
+#define RTP_MAX_SDES 256   /**< maximum text length for SDES */
 
 /* RTCP paquets use 0.5 % of the bandwidth */
 #define RTCP_TX_RATIO_NUM 5