usrp1: Update device API for frequency offset tuning

Commit 8e17df7374367d57 "Add option for baseband frequency offset",
modified the base device API to allow for RF tuning, which was never
updated for the USRP1.

Update the implementation to match the API, however, note actual offset
in the USRP1 remains unsupported.

Signed-off-by: Tom Tsou <tom@tsou.cc>
diff --git a/Transceiver52M/USRPDevice.cpp b/Transceiver52M/USRPDevice.cpp
index e00d54e..bba8bb9 100644
--- a/Transceiver52M/USRPDevice.cpp
+++ b/Transceiver52M/USRPDevice.cpp
@@ -600,7 +600,7 @@
 bool USRPDevice::setRxFreq(double wFreq) { return true;};
 #endif
 
-RadioDevice *RadioDevice::make(size_t sps, size_t chans, bool diversity)
+RadioDevice *RadioDevice::make(size_t sps, size_t chans, bool diversity, double)
 {
 	return new USRPDevice(sps, chans, diversity);
 }