platform/x86: ideapad-laptop: use appropriately typed variable to store the return value of ACPI methods

Use a variable with type `acpi_status` to store the return value of
ACPI methods instead of a plain `int`. And use ACPI_{SUCCESS,FAILURE}
macros where possible instead of direct comparison.
Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210203215403.290792-4-pobrn@protonmail.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>