ns2: delay NS_AFF_CAUSE_RECOVERY until NS-VC for data + sig are unblocked

Right now we end up in situations where only a NS-VC for data (BVCI != 0)
becomes unblocked, but the BSSGP and/or user application code is
notified that the NSE has recovered.

In the case of osmo-gbproxy, this will trigger a BVC-RESET on the
BVCI=0, but that obviously only works if the sig_weight > 0...

Closes: OS#4956
Change-Id: I933ee3969c052394d61ec6cf8c7c21d17957d9ab
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index 5dbc349..5404ed3 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -136,6 +136,12 @@
 	enum gprs_ns2_dialect dialect;
 
 	struct osmo_fsm_inst *bss_sns_fi;
+
+	/*! sum of all the data weight of _active_ NS-VCs */
+	uint32_t sum_data_weight;
+
+	/*! sum of all the signalling weight of _active_ NS-VCs */
+	uint32_t sum_sig_weight;
 };
 
 /*! Structure representing a single NS-VC */