Use the platform data to set the clk_freq when there is no DT configuration
available. The clk_freq in turn will determine the I2C speed mode.

In Quark, there is currently no other configuration mechanism other than
board files.
Signed-off-by: NRaymond Tan <raymond.tan@intel.com>
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: NHock Leong Kweh <hock.leong.kweh@intel.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>