ALSA: fireworks/bebob/oxfw/dice: enable to make as built-in

When committed to upstream, these four modules had wrong entries for
Makefile. This forces them to be loadable modules even if they're set
as built-in.

This commit fixes this bug.

Fixes: b5b04336('ALSA: fireworks: Add skelton for Fireworks based devices')
Fixes: fd6f4b0d('ALSA: bebob: Add skelton for BeBoB based devices')
Fixes: 1a4e39c2('ALSA: oxfw: Move to its own directory')
Fixes: 14ff6a09('ALSA: dice: Move file to its own directory')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>