uhd: smpl_buf: Use TIMESTAMP type in str_status

Other related functions use "TIMESTAMP timestamp" so let's use same
stuff in that function.

Change-Id: I016b1a7f8db379caebc1409ca11e5ae8b759d2d4
diff --git a/Transceiver52M/device/uhd/smpl_buf.cpp b/Transceiver52M/device/uhd/smpl_buf.cpp
index ae21369..f3fc323 100644
--- a/Transceiver52M/device/uhd/smpl_buf.cpp
+++ b/Transceiver52M/device/uhd/smpl_buf.cpp
@@ -138,11 +138,11 @@
 		return len;
 }
 
-std::string smpl_buf::str_status(size_t ts) const
+std::string smpl_buf::str_status(TIMESTAMP timestamp) const
 {
 	std::ostringstream ost("Sample buffer: ");
 
-	ost << "timestamp = " << ts;
+	ost << "timestamp = " << timestamp;
 	ost << ", length = " << buf_len;
 	ost << ", time_start = " << time_start;
 	ost << ", time_end = " << time_end;