arm: socfpga: dts: soc64: Add binman node of FIT image with ATF support

Add binman node to device tree to generate the FIT image for u-boot
(u-boot.itb) and OS kernel (kernel.itb).

u-boot.itb contains arm trusted firmware (ATF), u-boot proper and
u-boot device tree for ATF u-boot flow.

kernel.itb contains Linux Image and Linux device tree.

Signed-off-by: Siew Chin Lim <elly.siew.chin.lim@intel.com>