sb/amd: Remove dropped platforms

This code is now unused by any platform.

Change-Id: I60afbde6ead70f0c887866fc351b4a6a15a89287
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69120
Reviewed-by: Elyes Haouas <ehaouas@noos.fr>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/northbridge/amd/agesa/state_machine.h

@@ -87,8 +87,6 @@ void platform_AfterS3Save(struct sysinfo *cb, AMD_S3SAVE_PARAMS *S3Save);
 
 /* FCH callouts, not used with CIMx. */
 #define HAS_AGESA_FCH_OEM_CALLOUT \
-	CONFIG(SOUTHBRIDGE_AMD_AGESA_HUDSON) || \
-	CONFIG(SOUTHBRIDGE_AMD_AGESA_YANGTZE) || \
 	CONFIG(SOUTHBRIDGE_AMD_PI_AVALON) || \
 	CONFIG(SOUTHBRIDGE_AMD_PI_KERN)