[][Refactor mt7981 arm64 loadaddr to support ramdisk boot]

[Description]
Refactor mt7981 arm64 loadaddr to support ramdisk boot

[Release-log]
N/A

Change-Id: I2d24b917befa6cb3926e257afc8511fd8ce9befb
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5142287
1 file changed