ASoC: Add ADAU1X61 and ADAU1X81 CODECs common code

The ADAU1X61 and ADAU1X81 are very similar in the digital domain, but are quite
different in the analog domain. This patch adds support for the common parts of
the ADAU1X61 and ADAU1X81 CODECs.

The patch also restores some of the alphabetical order in the Makfile and
Kconfig.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>