efi_loader: bootbin: do not load an initrd if none is provided

efi_loader: bootbin: do not load an initrd if none is provided

Do not try to create an initrd device path nor try to register
an initrd with the EFI_LOAD_FILE2_PROTOCOL if none is provided.

Handle initrd installation in efi_binary_run_dp with
efi_install_initrd, imitating what is done for the fdt.

Fixes: 36835a9105c ("efi_loader: binary_run: register an initrd")
Reported-by: Weizhao Ouyang <o451686892@gmail.com>
Signed-off-by: Adriano Cordova <adriano.cordova@canonical.com>
Tested-by: Weizhao Ouyang <o451686892@gmail.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>