fastboot: if enabled use bootai for "fastboot boot" command

Signed-off-by: Michael Scott <michael.scott@linaro.org>
jetson-tk1 config changes

enable fastboot and fastboot buffer location / size
enable fastboot mmc flash device 0
enable bootai and android image suppot
ignore boot.img memory locations
set additional cmdline parameters

Signed-off-by: Michael Scott <michael.scott@linaro.org>