efi_loader: allow concatenation with contained end node

Allow appending a device-path to a device-path that contains an end node
as separator. We need this feature for creating boot options specifying
kernel, initrd, and dtb.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
8 files changed