Merge "Export TARGET_BOARD_PLATFORM to soong" into main am: b9294988b6

Original change: https://android-review.googlesource.com/c/platform/build/+/3284512

Change-Id: Iaedfa0b412be541a47b7da76e74a91da6dabf997
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>