We cannot assume that the BIOS will be correctly setting up the hardware, so
set some bits in various display registers to enable video output.  Allow an
advanced user to specify a frambuffer size, rather then probing the BIOS.  All
of these fixes were prompted by the OLPC effort.

[akpm@osdl.org: cleanups]
Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Acked-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>