platform/x86: toshiba_acpi: use memdup_user_nul

Use memdup_user_nul() helper instead of open-coding to simplify the
code.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
1 file changed