Following is an updated patch to add support for using the GPIO lines
on an Intel IXP42x SOC for I2C.  Changes since last patch include:

- Cleanups as per Jean Delvare's comments

- Rename functions as 42x instead of 425

- Change the comments at the top of the file to better reflect the
  purpose of this driver.

This code has been tested with the eeprom client driver and worked
w/o any problems.