If efi_init_obj_list() fails we cannot use the UEFI sub-system.
* Instead of having messages for this everywhere write an error message
in efi_init_obj_list().
* Always use (ret != EFI_SUCCESS) when checking the return value of
efi_init_obj_list().
* Remove the return code from the error message as it does not help
users to understand which initialization went wrong.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>