All the PCM ioctl ops of ALSA FireWire drivers do nothing but calling
the default handler.

Now PCM core accepts NULL as the default ioctl ops(*), so let's drop
altogether.

(*) commit fc033cbf ("ALSA: pcm: Allow NULL ioctl ops")
Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191210061145.24641-6-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>