Fix sparse warning:

sound/soc/amd/raven/acp3x-pcm-dma.c:561:24: warning:
 symbol 'acp3x_dai_i2s_ops' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>