Merge "mkbootimg: Add '--boot_signature' and mark '--gki-*' as deprecated" am: 8bfa493d8e am: 3abe52d850 am: 14c7d4b133

Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/1933195

Change-Id: Ie49166af9a3c4ada00faae8dfee98ad558058b44