cmd: acpi: check HW reduced flag in acpi list

On non x86 platforms the hardware reduce flag must be set in the FADT
table. Write an error message if the flag is missing.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Rebased on -next to use nomap, add hyphens:
Signed-off-by: Simon Glass <sjg@chromium.org>