ASoC: jz4740-i2s: Fix divider written at incorrect offset in register

The 4-bit divider value was written at offset 8, while the jz4740
programming manual locates it at offset 0.

Fixes: 26b0aad8

 ("ASoC: jz4740: Add dynamic sampling rate support to jz4740-i2s")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200306222931.39664-2-paul@crapouillou.net
Signed-off-by: Mark Brown <broonie@kernel.org>