ASoC PCM core deals the empty ioctl field now as default.
Let's kill the redundant lines.

Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20191210145406.21419-22-tiwai@suse.deSigned-off-by: Mark Brown <broonie@kernel.org>