library/GSUP_Types.ttcn: add READY-FOR-SM message

According to 3GPP TS 29.002, section 12.4, MAP-READY-FOR-SM is
used between the MSC and VLR as well as between the VLR and the
HLR to indicate that a subscriber has memory available for SMS.

This change replicates this service in GSUP as READY_FOR_SM_*.
The only mandatory IE for this service (excluding Invoke ID) is
'Alert Reason' that is replicated by OSMO_GSUP_SM_ALERT_RSN_IE.

Change-Id: If2256607527ecfcb10285583332fb8b0515d7c78
Related: OS#3587
1 file changed