pdch: Add mising pdch_ulc_release_node in Rx Cell Change Notif

All other RX CTRL block paths have it, this one was missing.

Change-Id: Ief315d7b6d4fea946d43e5bd87cf8a0394adc855
diff --git a/src/pdch.cpp b/src/pdch.cpp
index 727ffc6..5272f4b 100644
--- a/src/pdch.cpp
+++ b/src/pdch.cpp
@@ -754,6 +754,8 @@
 		ms = dl_tbf->ms();
 	} else { OSMO_ASSERT(0); }
 
+	pdch_ulc_release_fn(ulc, fn);
+
 	ms_update_l1_meas(ms, meas);
 	ms_nacc_start(ms, notif);
 }