ASoC: cs42xx8: Add codec driver support for CS42448/CS42888

This patch adds support for the Cirrus Logic CS42448/CS42888 Audio CODEC that
has six/four 24-bit AD and eight 24-bit DA converters.

[ CS42448/CS42888 supports both I2C and SPI control ports. As initial patch,
  this patch only adds the support for I2C. ]

Signed-off-by: Nicolin Chen <Guangyu.Chen@freescale.com>
Acked-by: Brian Austin <brian.austin@cirrus.com>
Acked-by: Paul Handrigan <Paul.Handrigan@cirrus.com>
Signed-off-by: Mark Brown <broonie@linaro.org>