u-boot->efi payload rEFInd cant handling bootargs

need to put all boot param into external fdt bootargs by appending or any sort of method.

the idea is to extend uboot fdt cmd to handling append boot param string. but the situation is rEFInd is handling this itself by searching vmlinux/vmlinuz/kernel-xxx file and boot afterward. no known u-boot logic is participate at this stage.  