ASoC: WM8580: Fix R8 initial value

Acc to WM8580 manual, the default value for R8 is 0x10, not 0x1c.

Signed-off-by: Seungwhan Youn <sw.youn@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@kernel.org