mfd: Add in XIIC to some configurations of timberdale

This patch adds in the Xilinx I2C bus driver to some of the
configurations of the timberdale MFD.

It provides the I2C devices to the XIIC via platform data in a
similar way as done to the ocores driver.

Signed-off-by: Richard Röjfors <richard.rojfors@pelagicore.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>