i2c-ibm_iic: Remove deprecated OCP style part

The deprecated OCP style driver part is used by the "old" arch/ppc
platform. This platform is scheduled for removal in June/July this year.
This patch now removes the OCP driver part from the IBM I2C driver.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>