ASoC: mediatek: mt8195: Make sure of_device_id table are NULL terminated

Fix the following coccicheck review:
./sound/soc/mediatek/mt8195/mt8195-mt6359.c:1657:1-2:
mt8195_mt6359_dt_match is not NULL terminated at line 1657

Fixes: 86a6b9c9

 ("ASoC: mediatek: mt8195: add machine support for max98390 and rt5682")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Link: https://lore.kernel.org/r/20220408100309.2495462-1-lv.ruyi@zte.com.cn
Signed-off-by: Mark Brown <broonie@kernel.org>