ASoC: SOF: mediatek: mt8195: Add pcm_pointer callback

Add pcm_pointer callback for mt8195 to support read
host position from DSP

Signed-off-by: Chunxu Li <chunxu.li@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220924033559.26599-3-chunxu.li@mediatek.com


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