Remove old AMD #define

Remove old AMD #define

The #define REQUIRED_CALLOUTS is no longer used on these platforms.

Change-Id: I536eb94119f1bc8f81e59ebefacdd4e04d0ed3ef
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: http://review.coreboot.org/540
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>