gb: Fix gprs_active_nsvc_by_nsei()

The state matching condition is inverted. This is corrected by this
fix.

Sponsored-by: On-Waves ehf
diff --git a/tests/gb/gprs_ns_test.ok b/tests/gb/gprs_ns_test.ok
index 5dc1e92..424d681 100644
--- a/tests/gb/gprs_ns_test.ok
+++ b/tests/gb/gprs_ns_test.ok
@@ -167,10 +167,7 @@
 NS UNITDATA MESSAGE to SGSN, BVCI 0x0000, msg length 18
 22 04 82 4a 2e 07 81 08 08 88 10 20 30 40 50 60 10 00 
 
-MESSAGE to SGSN, msg length 22
-00 00 00 00 22 04 82 4a 2e 07 81 08 08 88 10 20 30 40 50 60 10 00 
-
-result (BSSGP RESET) = 22
+result (BSSGP RESET) = -16
 
 --- Make connection to SGSN alive ---
 
@@ -200,10 +197,7 @@
 NS UNITDATA MESSAGE to SGSN, BVCI 0x0000, msg length 18
 22 04 82 4a 2e 07 81 08 08 88 10 20 30 40 50 60 10 00 
 
-MESSAGE to SGSN, msg length 22
-00 00 00 00 22 04 82 4a 2e 07 81 08 08 88 10 20 30 40 50 60 10 00 
-
-result (BSSGP RESET) = 22
+result (BSSGP RESET) = -16
 
 --- Unblock connection to SGSN ---
 
@@ -231,7 +225,10 @@
 NS UNITDATA MESSAGE to SGSN, BVCI 0x0000, msg length 18
 22 04 82 4a 2e 07 81 08 08 88 10 20 30 40 50 60 10 00 
 
-result (BSSGP RESET) = -16
+MESSAGE to SGSN, msg length 22
+00 00 00 00 22 04 82 4a 2e 07 81 08 08 88 10 20 30 40 50 60 10 00 
+
+result (BSSGP RESET) = 22
 
 --- Send empty message with BVCI to SGSN ---
 
@@ -239,7 +236,10 @@
 NS UNITDATA MESSAGE to SGSN, BVCI 0x0102, msg length 0
 
 
-result ([empty]) = -16
+MESSAGE to SGSN, msg length 4
+00 00 01 02 
+
+result ([empty]) = 4
 
 ===== NS protocol test END