Make 'fastboot boot' command support boot header version 2

New arguments 'dtb' and 'dtb-offset' have been added to
support boot image header version 2 for the 'fastboot boot'
and 'fastboot flash:raw boot' commands.

Test: fastboot boot Image.lz4 --dtb <dtb_path> --header-version 2
Test: fastboot flash:raw boot Image.lz4 --dtb <dtb_path>
--header-version 2
Bug: 111136242

Change-Id: Idf5c2eb138609dc7e915e80c4db64677c89f24b6