Merge "pixel3_mainline: Add changes to get pixel3_mainline building a boot.img (v3)" am: 679c9c12f8 am: 7e7b7b22b5 am: 477eb10c68

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/1354425

Change-Id: I32190a1b0d92efa31288278276d9586bb37cb0cb