uninorth-agp section mess

'aperture' is declared devinitdata (the whole word of it) and
is used from ->fetch_size() which can, AFAICS, be used on
!HOTPLUG after init time.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>