MIPS: add initial infrastructure for device-tree files
Prepare sub-folder for device-tree files. Make support for
device-tree on MIPS available in Kbuild/Kconfig.
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>