ns: Log when sending fails (Coverity)

Currently the return value of the gprs_ns_tx family of functions is
often ignored. This is not a serious issue, since the successful
delivery of the messages is neither guaranteed nor acknowledged by
the network layer anyway.

Nevertheless this commit adds logging (level INFO) to gprs_ns_tx and
gprs_ns_msgb_alloc. The definition of the latter has been moved from
the header file to gprs_ns.c.

Fixes: Coverity CID 1040678, 1040679, 1040680, 1040681, 1040682,
   1040683, 1040684, 1040686, 1040687, 1040688, 1111545,
   1240203, 1240204
Sponsored-by: On-Waves ehf
3 files changed