gprs_ns2_nsvc_by_sockaddr_nsei is doing the lookup within a NSE.
gprs_ns2_nsvc_by_sockaddr_bind is doing the lookup within a bind.
Make both function look similiar and take similiar arguments.
Change-Id: Ia499fc279013668abe7348e578a0768f7d16faf9
I was reading through the code and noticed many functions not
documented yet, or with incomplete documentation. Change that.
Change-Id: I85a2419604a9fd9ff3c4828a7463e222652f77bf