platform/x86: fujitsu-laptop: allocate fujitsu_laptop in acpi_fujitsu_laptop_add()

Only allocate memory for struct fujitsu_laptop when the FUJ02E3 ACPI
device is present.  Use devm_kzalloc() for allocating memory to simplify
cleanup.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>