ASoC: rockchip: correct the spdif clk

The spdif mclk should be 128 times of sample rate, and there is a
internal divider, the real rate of spdif mclk is mclk / (div + 1).
Hence, the original driver always get the good frequency for
48000/96000/44100/192000. But for 32000, the mclk is incorrect,
it should be 32000*128, but get 48000*128. Do not use the internal
divider here, just set all mclk to 128 * sample rate directly.

Signed-off-by: Chris Zhong <zyw@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>