ANDROID: Handle a new init_boot partition that contains ramdisk

This new init_boot partition contains the ramdisk the used to live in
the boot partition. The boot partition will no longer contain that
ramdisk.

The bootloader remain flexible to be able to use the ramdisk from
boot or init_boot partititon.

Test: Boot cuttlefish
Bug: 203698939

Change-Id: I687ec1264494e9fe85321414b64eeebbc0e4e156
4 files changed