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

fbcon=rotate:2
Signed-off-by: NAntonino Daplas <adaplas@pol.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>