[Chrono] Fix !HAVE_FUTIMENS build

If we don't have futimens(), we fall back to futimes(), which only supports
microsecond timestamps. In that case, we need to explicitly cast away the extra
precision in setLastModificationAndAccessTime().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284977 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/Unix/Path.inc

@@ -451,7 +451,8 @@ std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
   return std::error_code();
 #elif defined(HAVE_FUTIMES)
   timeval Times[2];
-  Times[0] = Times[1] = sys::toTimeVal(Time);
+  Times[0] = Times[1] = sys::toTimeVal(
+      std::chrono::time_point_cast<std::chrono::microseconds>(Time));
   if (::futimes(FD, Times))
     return std::error_code(errno, std::generic_category());
   return std::error_code();