Chris Newport and Thomas Bogendoerfer have been working to get the
sun4d port functional again. This patch updates 2.6.10-rc3 to a current
snapshot of their work. It does the following 3 things:

(1) add sun4d hook to sbus_bus_ranges_init()
(2) fix up pgd_offset() call in sun4d iommu code
(3) fix up sun4d's definition of current
Signed-off-by: Chris Newport <crn@netunix.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>