Revert "arm: mvebu: x240: Use i2c-gpio instead of built in controller"

This reverts commit 5c1c6b73. The reason
for switching to i2c-gpio was due to an issue we were seeing in the
Linux kernel where the CPU would lock up on certain adverse I2C bus
conditions. We were never able to reproduce the lockup in U-Boot but
assumed that was probably just luck.

Since then we have discovered that the lock up was due to the I2C
transaction offload engine in the I2C controller not coping with the
adverse bus conditions (basically it thinks there's another master and
waits for a STOP condition that never comes). U-Boot doesn't use the I2C
offload feature so is not susceptible to the lockup.

We can therefore safely return to using the built-in I2C controller.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>