ASoC: wm8960: Move register initialisation to I2C driver probe()

We must ensure that the clocking configuration is valid as rapidly as possible.
And do software reset before the others registers updates, or the registers
will be reset to the default state.

Signed-off-by: Zidan Wang <b50113@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>