ntdll: Don't consider a 0-byte read from a serial port as a broken pipe.

dlls/ntdll/file.c

@@ -599,11 +599,23 @@ NTSTATUS WINAPI NtReadFile(HANDLE hFile, HANDLE hEvent,
             if (!result || total == length)
             {
                 if (total)
+                {
                     status = STATUS_SUCCESS;
-                else
-                    status = (type == FD_TYPE_FILE || type == FD_TYPE_CHAR) ? STATUS_END_OF_FILE : STATUS_PIPE_BROKEN;
                     goto done;
                 }
+                switch (type)
+                {
+                case FD_TYPE_FILE:
+                case FD_TYPE_CHAR:
+                    status = STATUS_END_OF_FILE;
+                    goto done;
+                case FD_TYPE_SERIAL:
+                    break;
+                default:
+                    status = STATUS_PIPE_BROKEN;
+                    goto done;
+                }
+            }
         }
         else
         {