SWDEV-369548 - Added getProcessId function in Os:: and change log functions to use that.

Change-Id: Ib64ee4d65a5212af7a4a95f80173b7ff8382340f

rocclr/utils/flags.cpp

@@ -20,6 +20,7 @@
 
 #include "top.hpp"
 #include "utils/flags.hpp"
+#include "os/os.hpp"
 
 #include <unordered_map>
 #include <string>
@@ -156,7 +157,7 @@ bool Flag::init() {
   if (!flagIsDefault(AMD_LOG_LEVEL)) {
     if (!flagIsDefault(AMD_LOG_LEVEL_FILE)) {
       std::string fileName = AMD_LOG_LEVEL_FILE;
-      fileName = fileName + "_" + std::to_string(getpid());
+      fileName = fileName + "_" + std::to_string(Os::getProcessId());
       outFile = fopen(fileName.c_str(), "w");
     }
   }