We used to force the obvious deep structure of all objects which
export symbols into a flat list in include/linux/modules. This
initially caused the restriction the no two exporting objects could
have the same name (Ever wondered why there's ksyms.c and
i386_ksyms.c?)

With the ALSA merge this restriction was mostly lifted by some hack,
but some cases still don't work right (Hi XFS). As it's much cleaner
to just use a normal tree under include/linux/modules, reflecting the
source tree, we now do just that.