i2c: Add support for I2C bus on Freescale CPM1/CPM2 controllers

This driver uses the port of 2.4 code from Vitaly Bordug
<vitb@kernel.crashing.org> and the actual algorithm used by the i2c
driver of the DBox code on cvs.tuxboc.org from Felix Domke
(tmbinc@gmx.net) and Gillem (htoa@gmx.net) converted to an
of_platform_driver. Tested on CPM1 (MPC823 on dbox2 hardware) and
CPM2 (MPC8272).

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>