uhd: Fix Tx-RX timing offset setting

Integer timestamp offset was set to zero due to bad cast-operator
precedence.

Change-Id: Ib1f524cc86416699b3c143e5faddb33d61380767
diff --git a/Transceiver52M/UHDDevice.cpp b/Transceiver52M/UHDDevice.cpp
index ecf2c34..233d465 100644
--- a/Transceiver52M/UHDDevice.cpp
+++ b/Transceiver52M/UHDDevice.cpp
@@ -437,7 +437,7 @@
 	tx_rate = usrp_dev->get_tx_rate();
 	rx_rate = usrp_dev->get_rx_rate();
 
-	ts_offset = (TIMESTAMP) desc.offset * rx_rate;
+	ts_offset = static_cast<TIMESTAMP>(desc.offset * rx_rate);
 	LOG(INFO) << "Rates configured for " << desc.str;
 }