[boot] uboot-lantiq: enable parallel building

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
[boot] uboot-lantiq: add packages for Lantiq EASY50712

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
[boot] uboot-lantiq: add packages for Lantiq EASY80920

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
[boot] uboot-lantiq: add packages for various Arcadyan boards

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>