ARM: dts: keystone-k2g: Add I2C nodes

Add nodes for the various I2C instances.

Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <ssantosh@kernel.org>