gb: When sending on a NS-VC group use the first active NS-VC

Currently this first NS-VC with a matching NSEI is always used to
send a UNITDATA message via gprs_ns_sendmsg(). If the NS-VC found is
either dead or blocked, an error is returned.

This patch changes to code to skip blocked or dead NS-VCs while
searching and return the error if no usable NS-VC is found. This
makes it possible to have several NS-VCs per connection group.

Sponsored-by: On-Waves ehf
1 file changed