ASoC: pcm: Make ioctl ops optional

Now PCM core accepts the NULL ioctl ops as default, and passing a proper
ioctl ops is no longer mandatory.  Adjust soc_new_pcm() to allow also
the NULL for component ioctl ops, too.

Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20191121190709.29121-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>