[PATCH] add hardware I2C support for ARM IMX23

[Sander van Ginkel]

tested with:
CONFIG_I2C_MXS=m
CONFIG_I2C_MXS=y

in combination with CONFIG_GPIO_MXS enabled and disabled

used kernels: 3.6 and 3.7.0-rc6

My I2C slave is a PCF8575 i/o expander with some LEDs at the output.
These are controlled through sysfs.

Just tested with "i2cdetc -y -r 0" that crashes with  "BUG: soft lockup 
- CPU#0 stuck for 22s!"
according to the docs (IMX23RM.pdf) the interrupts for I2C are 26 and 27 
that why I assigned these two in the dts.