gprs_ns2: move sns_event into internal.h to direct emit events

When other parts of ns2 requires to emit an event to the SNS fsm it would
need a proxy function because the events are private to the
SNS file. To circumvent creating multiple proxy function make the events
available via a header file.

Change-Id: I8e3fae4367c112b5a71bffb33c302d903855cddc
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index 95efbae..6096263 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -320,6 +320,23 @@
 	void (*free_bind)(struct gprs_ns2_vc_bind *driver);
 };
 
+enum ns2_sns_event {
+	NS2_SNS_EV_REQ_SELECT_ENDPOINT,	/*!< Select a SNS endpoint from the list */
+	NS2_SNS_EV_RX_SIZE,
+	NS2_SNS_EV_RX_SIZE_ACK,
+	NS2_SNS_EV_RX_CONFIG,
+	NS2_SNS_EV_RX_CONFIG_END,		/*!< SNS-CONFIG with end flag received */
+	NS2_SNS_EV_RX_CONFIG_ACK,
+	NS2_SNS_EV_RX_ADD,
+	NS2_SNS_EV_RX_DELETE,
+	NS2_SNS_EV_RX_CHANGE_WEIGHT,
+	NS2_SNS_EV_RX_ACK,			/*!< Rx of SNS-ACK (response to ADD/DELETE/CHG_WEIGHT */
+	NS2_SNS_EV_REQ_NO_NSVC,		/*!< no more NS-VC remaining (all dead) */
+	NS2_SNS_EV_REQ_NSVC_ALIVE,		/*!< a NS-VC became alive */
+	NS2_SNS_EV_REQ_ADD_BIND,		/*!< add a new local bind to this NSE */
+	NS2_SNS_EV_REQ_DELETE_BIND,		/*!< remove a local bind from this NSE */
+};
+
 enum ns2_cs ns2_create_vc(struct gprs_ns2_vc_bind *bind,
 			       struct msgb *msg,
 			       const struct osmo_sockaddr *remote,