PCM core deals the empty ioctl field now as default(*).
Let's kill the redundant lines.
(*) commit fc033cbf6f
("ALSA: pcm: Allow NULL ioctl ops")
Link: https://lore.kernel.org/r/20191210061145.24641-22-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>