platform/x86: thinkpad_acpi: Fix compiler warning about uninitialized err variable

platform/x86: thinkpad_acpi: Fix compiler warning about uninitialized err variable

err is always set because if we get here then dytc_profile_available
is always one of DYTC_FUNCMODE_MMC or DYTC_FUNCMODE_PSC, but the
compiler cannot now that, so initialize err to 0 to avoid a
compiler warning about err being uninitialized.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220309170532.343384-1-hdegoede@redhat.com