[BUG] Fix drivers/memory O= build

Tue Apr 10 06:55:16 PDT 2018

* Dave Gerlach <d-gerlach at ti.com> [180409 16:07]:
> I've inlined the changes below. I will send a proper split up series if it's
> considered acceptable.

Seems fine from my point of view. No need to split the patch, best to
do the fix as a single patch.

We should test build it also with make randconfigs though.

So assuming others are OK with this and it does not introduce
new randconfig build errors:

Acked-by: Tony Lindgren <tony at atomide.com>