Remove traps and check pointer is valid before using
Fix for MSRP.End.c.35.1.1 - MSRPDU Destination MAC Address

Now checks the Destination MAC Address of the PDU
before processing.
Now tracks remote Talker Advertise attrs for single port
Proper fix for commit 9dcf8a50.

Still need to check if the stream ID has changed
because the SRP reservation will not change if 
state remains POTENTIAL.