i82801gx: Kill unused TCG and SMI1

SMI1 is being written to but never read from.

Change-Id: I82c0800713e3093eb1317b5e1f6f228771134857
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/6808
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>