wifi: iwlwifi: acpi: fix WPFC reading

The code reading the WPFC table needs to take into account
the domain type (first element in the package), shouldn't
leak the memory if it fails, and has a bad comment. Fix all
these issues.

Fixes: c4c95454 ("wifi: iwlwifi: implement WPFC ACPI table loading")
Reported-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Gregory Greenman Gregory <gregory.greenman@intel.com>
Link: https://msgid.link/20240128084842.2afeb476b62d.I200568dc42a277e21c12be99d5aaa39b009d45da@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>