keymap: pass full keyboard state to keysym2scancode

Pass the keyboard state tracker handle down to keysym2scancode(),
so the code can fully inspect the keyboard state as needed.  No
functional change.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20190122092814.14919-8-kraxel@redhat.com