Deprecate mkbootimg_args.json by fully support "--format=mkbootimg" am: 07c6063146 am: de73fd2a36

Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/1693414

Change-Id: Ie46068732f1982292e1f2c398561a4f3d8823676