The ACPI spec 6.3 chapter 6.1.10 states that _STR has to return a buffer containing UTF-16 characters. Add function to generate Unicode names and use it for _STR. It will replace non-ASCII characters with '?'. Use the introduced function in IPMI driver. Fixes ACPI warning shown in fwts. Change-Id: I16992bd449e3a51f6a8875731cd45a9f43de5c8c Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/37789 Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>