hte: Use kasprintf() instead of fixed buffer formatting

Improve readability and maintainability by replacing a hardcoded string
allocation and formatting by the use of the kasprintf() helper.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Dipen Patel <dipenp@nvidia.com>
Signed-off-by: Dipen Patel <dipenp@nvidia.com>