Use 2X for bidir p2p memory bandwidth calc

[ROCm/hip-tests commit: f19c685f88]

projects/hip-tests/samples/1_Utils/hipBusBandwidth/hipBusBandwidth.cpp

@@ -922,7 +922,7 @@ void RunBenchmark_P2P_Bidir(ResultDatabase &resultDB) {
                         std::cerr << "size " << sizeToString(thisSize) << " took " << t << " ms\n";
                     }
 
-                    double speed = (double(sizeToBytes(thisSize) * p_beatsperiteration) / (1000*1000)) / t;
+                    double speed = (double(sizeToBytes(2*thisSize) * p_beatsperiteration) / (1000*1000)) / t;
                     char sizeStr[256];
                     if (p_beatsperiteration>1) {
                         sprintf(sizeStr, "%9sx%d", sizeToString(thisSize).c_str(), p_beatsperiteration);