ASoc: rt5631: Constify static struct coeff_clk_div

coeff_div is only read from, so make it const to show the intent.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20210224211918.39109-5-rikard.falkeborn@gmail.com


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