Add support for 180-degree (upside down) rotation of the console.  To
activate, boot with:

fbcon=rotate:2
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>