acer-wmi: remove non-used acer_quirks struct definition

Remove non-used acer_quirks struct definition.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Garrett <mjg@redhat.com>