ALSA: firewire-tascam: add Kconfig entry for TASCAM FW-1804

I forgot it.

Fixes: 3e78e151('ALSA: firewire-tascam: add support for FW-1804')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>