- Fix race condition in option_table.h generation by moving the include

- Fix race condition in option_table.h generation by moving the include
  statement to those files that actually need it. This significantly
  reduces the number of dependencies, so it's no longer extremely ugly to
  specify them manually (see the src/pc80/Makefile.inc portion)
- Add double include guards around option_table.h defines
- Also, drop the AMD DBM690T work around for the issue

Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Myles Watson <mylesgw@gmail.com>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5838 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1