Passing the iov_iter to the process callback is rather buggy, as the
iterator has been already processed for playback.  Similarly, it makes
the copy for capture buggy after the process callback reading the
iterator out.  Moreover, all existing process callbacks don't refer to
the passed iterator at all.  So, it's better to drop the argument from
the process callback.

Fixes: 9bebd654 ("ASoC: dmaengine: Use iov_iter for process callback, too")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wje+VkXjjfVTmK-uJdG_M5=ar14QxAwK+XDiq07k_pzBg@mail.gmail.comReviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230831130457.8180-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>