Don't use a pointer-to-flags/timestamp in ff_rm_parse_packet(); the function

Don't use a pointer-to-flags/timestamp in ff_rm_parse_packet(); the function
used to return packet data, which might update the flags/timestamp to be
used for the next packet data returned by the demuxer. However, that was
separated out into a new function, and the flags/timestamp are thus never
updated within ff_rm_parse_packet() anymore, and thus do not need to be
a pointer.

Originally committed as revision 19539 to svn://svn.ffmpeg.org/ffmpeg/trunk