certify_bootimg: support --extra_footer_args am: f754a7c3b8 am: a86f4ddbf6 am: 12bcad6963 am: ee599a6116 am: de1a7fb48a

Original change: https://android-review.googlesource.com/c/platform/system/tools/mkbootimg/+/2104149

Change-Id: I5de9e66959a407985ec9eb1a8c4e485dbb304c06
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>