mainboard: Trivial - Make AGESA board include consistent

Change-Id: If6cb99469f56fff8f88b294b625f0a5205ec540b
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/7238
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>