platform/x86: hp-wmi: Remove unused macro helper

The commit d8193cff
    ("platform/x86: hp-wmi: Standardize enum usage for constants")
introduced a macro that had been never used.

Remove it.

Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
[andy wrote commit message]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>