ASoC: SSM2602: Fix default register cache

Some of the values in the default register cache did not represent the codecs
state after reset. This patch fixes it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>