ubifs: add sama5d4ek setting

need call like: sudo ./gen_ubi.sh sama5d4ek
This setting is adapter to sama5d4ek rev.D nand flash.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
jenkins: yocto: add script to build yocto by fetch github code

Signed-off-by: Josh Wu <josh.wu@atmel.com>
jenkins: yocto: support build more machine type

Signed-off-by: Josh Wu <josh.wu@atmel.com>
ubifs: add sama5d4ek subpage support settings

Signed-off-by: Josh Wu <josh.wu@atmel.com>
script: shell: add a script can update md5sum and sha256sum for .bb file

Signed-off-by: Josh Wu <josh.wu@atmel.com>
script: It can build yocto core-image-minimal for all machines.

Signed-off-by: Josh Wu <josh.wu@atmel.com>