trx_rate_ctr: Fix locking wrong mutex

It was notcied due to sometimes causing deadlock at shutdown time.

Fixes: 92ba59dacffe79f4c987154bc63c6eacd8c3605f
Change-Id: I49bea4b0ae469794b5c80ee8fa4f275914a5194c
diff --git a/CommonLibs/trx_rate_ctr.cpp b/CommonLibs/trx_rate_ctr.cpp
index 76aff7d..6391a38 100644
--- a/CommonLibs/trx_rate_ctr.cpp
+++ b/CommonLibs/trx_rate_ctr.cpp
@@ -159,7 +159,7 @@
 	size_t chan;
 	struct rate_ctr *ctr;
 	LOGC(DMAIN, NOTICE) << "Main thread is updating Transceiver counters";
-	dev_rate_ctr_mutex.lock();
+	trx_rate_ctr_mutex.lock();
 	for (chan = 0; chan < chan_len; chan++) {
 		if (trx_ctrs_pending[chan].chan == PENDING_CHAN_NONE)
 			continue;