BTS_Tests: fix comment

The testcase is about PCH, not AGCH

Related: OS#5927
Change-Id: I5c2aa1aab261a0f4bfb24b4be7af29c1d814d37a
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 93b0ddf..c5cc9c7 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -5806,7 +5806,7 @@
 	}
 }
 
-/* Send AGCH from PCU; check it appears on Um side */
+/* Send PCH from PCU; check it appears on Um side */
 testcase TC_pcu_data_req_pch() runs on test_CT {
 	timer T := 3.0;
 	f_init_with_pcuif();