sgsn: Pass subscriber error causes to the GMM layer

This patch extends gsm0408_gprs_access_denied and
gsm0408_gprs_access_cancelled to accept GMM cause codes. These are
then passed to the MS, unless gsm0408_gprs_access_cancelled is called
with cause 0 (no error -> updateProcedure).

Since gsm0408_gprs_access_denied uses GMM_CAUSE_GPRS_NOTALLOWED if
the cause is not set, and the subscriber's error_cause is never set
(and thus always 0), the SGSN's behaviour does not change with this
patch.

Sponsored-by: On-Waves ehf

Conflicts:
	openbsc/include/openbsc/gprs_sgsn.h

[hfreyther: Conflict due the removal of the unused
authenticate flag]
5 files changed
tree: 00dbf95af936c1fc59196580d047265e1b0c1085
  1. debian/
  2. hlrsync/
  3. linux-kernel/
  4. openbsc/
  5. wireshark/
  6. README