tree f1d3c25a332c1b84d2a569e221b15b6d90f73bf8
parent f8dde8198ba2d1cabb1b6e9c46e0f6bf6d8eda65
author Alex Van Damme <atv@google.com> 1547493229 -0800
committer Alex Van Damme <atv@google.com> 1547497044 +0000

Push some definitions out of preamble.mk into board/

- Require including board/arch.mk
- Move overrides of prebuilts into board/arch.mk to allow per-board
choices
- Move BOOT/ROOTFS_SIZE definitions into board/arch.mk
- Append BOARD_PACKAGES_EXTRA to PACKAGES_EXTRA, to allow per-board
preinstalled packages

Change-Id: I76f00e03036d56bcfd3246c271413b51d2871332