Merge "pixel3_mainline: Add changes to get pixel3_mainline building a boot.img (v3)" am: 679c9c12f8 am: 7e7b7b22b5 am: 477eb10c68 am: 21cd010ab8 am: ee06878011

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

Change-Id: I2a697f729ec8d7443bbd00400b7bce43bdb462b3