i2c-cpm: Fix to takeback i2c bus master-ship after a collision

In case of collision on i2c bus the controller which lost bus mastership
stays as a slave for all subsequent transfers. This results in the i2c
controller never writing to the bus for future transactions, resulting
in i2c transfer timeouts.
  This fix checks for a collision on last I2C transaction and sets the
I2COM_MASTER bit for the new transaction.

Signed-off-by: Sachin Surendran <sachin.surendran@alliedtelesis.co.nz>
Signed-off-by: Scott Wood <scottwood@freescale.com>