Migrate fsp_206ax to SMM_MODULES

This gets rid of ugly tseg_relocate for fsp_bd82x6x.

This is adaptation of a3e41c0896

Change-Id: I4e80e6e98d3a6da3e3e480e9368fae1b3ed67cd6
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/10353
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/northbridge/intel/fsp_sandybridge/northbridge.h

@@ -102,6 +102,7 @@
 
 #define TOM		0xa0
 #define TOUUD		0xa8	/* Top of Upper Usable DRAM */
+#define BGSM		0xb4	/* Base GTT Stolen Memory */
 #define TSEG		0xb8	/* TSEG base */
 #define TOLUD		0xbc	/* Top of Low Used Memory */