ASoC: qcom: Convert to generic PCM copy ops

This patch converts the qcom lpass driver code to use the new unified
PCM copy callback.  It's a straightforward conversion from *_user() to
*_iter() variants.

Note that copy_from/to_iter() returns the copied bytes, hence the
error condition is adjusted accordingly.

Reviewed-by: Mark Brown <broonie@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Banajit Goswami <bgoswami@quicinc.com>
Link: https://lore.kernel.org/r/20230815190136.8987-21-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>