Transceiver52M: Set variable thread priority levels

The transceiver and underlying device drivers are threaded. use
the following priority levels.

0.50 - UHD driver internal threads
0.45 - Receive device drive thread
0.44 - Transmit device drive thread
0.43 - UHD asynchronous update thread (error reporting)
0.42 - Receive burst processing thread(s)

Signed-off-by: Thomas Tsou <tom@tsou.cc>
diff --git a/Transceiver52M/radioInterface.h b/Transceiver52M/radioInterface.h
index 1e58ecb..124cdc3 100644
--- a/Transceiver52M/radioInterface.h
+++ b/Transceiver52M/radioInterface.h
@@ -133,7 +133,7 @@
   double fullScaleOutputValue();
 
   /** set thread priority on current thread */
-  void setPriority() { mRadio->setPriority(); }
+  void setPriority(float prio = 0.5) { mRadio->setPriority(prio); }
 
   /** get transport window type of attached device */ 
   enum RadioDevice::TxWindowType getWindowType() { return mRadio->getWindowType(); }