armv8: fsl-layerscape: Update I2C clock divider

By default, i2c input clock is programmed at
platform clk / 2 in u-boot, but this is not
correct for all the platforms,
Update I2C clock divider's default values as per
SoC (LS1012A, LS1028A, LX2160A and LS1088A).

Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>