This allows machine drivers to build without ifdefs if they have
full constraints. Suggested by machine drivers contributed by
Haojian Zhuang <haojian.zhuang@gmail.com>.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NLiam Girdwood <lrg@slimlogic.co.uk>