MIPS: Netlogic: Platform changes for XLR/XLS I2C

Add platform code for XLR/XLS I2C controller and devices. Add
devices on the I2C bus on the XLR/XLS developement boards.

Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3757/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>