[PATCH] cxl: Fix build failure due to -Wunused-variable behaviour change

[Anton Blanchard]

Hi Torsten,

> > -ccflags-y := -Werror
> > +ccflags-y := -Werror -Wno-unused-const-variable
> 
> JFYI, my gcc-4.3 does not like this switch.
> What's the minimum compiler version to build this code?

-Werror is such a moving target. I'm also seeing issues when building
with clang, eg:

drivers/misc/cxl/native.c:223:20: warning: unused function
'detach_spa' [-Wunused-function]

Anton