[PGO] Fix the type of the formated variable

[mstojanovic]

Summary

Change the format type of Value to PRIu64 since it is a uint64_t.
The problem was detected on mips boards building 32-bit binaries, where it was printing junk values and causing test failure.

[davidxl]

lgtm

llvm/trunk/tools/llvm-profdata/llvm-profdata.cpp

for (size_t I = 0; I < NS; ++I) {
     for (uint32_t V = 0; V < NV; V++)
       SiteSum += VD[V].Count;
     if (SiteSum == 0)
       SiteSum = 1;
 
     for (uint32_t V = 0; V < NV; V++) {
       OS << "\t[ " << format("%2u", I) << ", ";
       if (Symtab == nullptr)
-        OS << format("%4u", VD[V].Value);
+        OS << format("%4" PRIu64, VD[V].Value);
       else
         OS << Symtab->getFuncName(VD[V].Value);
       OS << ", " << format("%10" PRId64, VD[V].Count) << " ] ("
          << format("%.2f%%", (VD[V].Count * 100.0 / SiteSum)) << ")\n";
     }
   }
 }