Input: atkbd - add keymap quirk for Inventec Symphony systems

The Zepto 6615WD laptop (rebranded Inventec Symphony system) needs a
key release quirk for its volume keys to work. The attached patch adds
the quirk to the atkbd driver.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=460237

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>