efi_loader: implement deprecated Unicode collation protocol

In EFI 1.10 a version of the Unicode collation protocol using ISO 639-2
language codes existed. This protocol is not part of the UEFI specification
any longer. Unfortunately it is required to run the UEFI Self Certification
Test (SCT) II, version 2.6, 2017. So we implement it here for the sole
purpose of running the SCT. It can be removed once a compliant SCT is
available.

The configuration option defaults to no.

Signed-off-by: Rob Clark <robdclark@gmail.com>

Most of Rob's original patch is already merged. Only the deprecated
protocol is missing. Rebase it and make it configurable.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>