mx31ads: Initial support for Wolfson Microelectronics 1133-EV1 module

mx31ads: Initial support for Wolfson Microelectronics 1133-EV1 module

The i.MX31ADS supports pluggable PMU modules, including the WM835x based
Wolfson Microelectronics 1133-EV1. These boards provide power, audio,
RTC and watchdiog services to the system. This patch adds initial support
for those boards in I2C mode.

Currently support is limited by the available support for the features
of the i.MX31 in the mainline kernel.  Some further work will be needed
once other PMU modules are supported and once there is SPI support.
Many of the regulator constraints will be sharable with other PMU
boards.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>