ASoC: generic-dmaengine: Drop superfluous ioctl PCM ops

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

Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20191210145406.21419-16-tiwai@suse.de


Signed-off-by: Mark Brown <broonie@kernel.org>