x86, olpc-xo1-sci: Add lid switch functionality

Configure the XO-1's lid switch GPIO to trigger an SCI interrupt,
and correctly expose this input device which can be used as a wakeup
source.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-9-git-send-email-dsd@laptop.org
Acked-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>