platform/x86: think-lmi: Remove unnecessary casts for attributes

These casts are unnecessary and could break if structure layouts are
randomized or implementation details change.
Use the proper syntax that works without casts.

Also remove some unnecessary braces that checkpatch complains about.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230329-think-lmi-attrs-v1-1-5794f2367cc2@weissschuh.net


Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>