ASoC: fsl: imx-pcm-rpmsg: Add SNDRV_PCM_INFO_BATCH flag

The rpmsg pcm device is a device which should support
double buffering.

Found this issue with pipewire. When there is no
SNDRV_PCM_INFO_BATCH flag in driver, the pipewire will
set headroom to be zero, and because rpmsg pcm device
don't support residue report, when the latency setting
is small, the "delay" always larger than "target" in
alsa-pcm.c, that reading next period data is not
scheduled on time.

With SNDRV_PCM_INFO_BATCH flag in driver, the pipewire
will select a smaller period size for device, then
the task of reading next period data will be scheduled
on time.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1694414287-13291-1-git-send-email-shengjiu.wang@nxp.com


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