SR codec framesize support in RTP ToC SR byte

To estmate the correct frame size of a SR frame in RTP payload, it is
important to know the codec's framesize employed in addition to the
bitrate. This can be propagated from SDP, this work extends to resolve
this info from the ToC byte which makes it easier to parse an rtp dump
even if the sdp negotiated codec framesize is not available.

Signed-off-by: Ripinder Singh <ripinder.singh@dolby.com>