lenovo/x200: Move video ASL code to northbridge.

Change-Id: I58760500252e78da947685c18201b6d446368333
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6729
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>