ANDROID: Enable u-boot bootloader boot mode back

Since fastboot is supported, enable bootloader boot mode back
and provide fastboot tcp default environment to start TCP fastbooot

Test: launch_cvd + adb reboot bootloader + fastboot connect
Bug: 274924654
Change-Id: Ie9111e10c101f92544fb0e32a6aef3753841583d
Signed-off-by: Dmitrii Merkurev <dimorinny@google.com>
2 files changed