I2C of helpers used to live in of_i2c.c but experience (from SPI) shows
that it is much cleaner to have this in the core. This also removes a
circular dependency between the helpers and the core, and so we can
finally register child nodes in the core instead of doing this manually
in each driver. So, fix the drivers and documentation, too.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This patch adds support for the I2C bus controllers found on Wondermedia
8xxx-series SoCs. Only master-mode is supported.
Signed-off-by: NTony Prisk <linux@prisktech.co.nz>
[wsa: fixed one macro to shift 8 instead of 16]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>