Avoid ../../.. paths in ASL files

Avoid ../../.. paths in ASL files

The current directory is always part of the search path of cpp when
using #include "..."

Change-Id: I74fe39e0c79835e4b9a927afcbeab21040d8ae52
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/648
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>