reset: Finalize move to new API

Move soft_reset() to `southbridge/amd/common/` it's only used for
amdfam10 now.

Drop hard_reset() for good.

Change-Id: Ifdc5791160653c5578007f6c1b96015efe2b3e1e
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/29059
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/amd/family_10h-family_15h/init_cpus.c

@@ -27,6 +27,8 @@
 #include <northbridge/amd/amdht/porting.h>
 #include <northbridge/amd/amdht/h3ncmn.h>
 
+#include <southbridge/amd/common/reset.h>
+
 #if IS_ENABLED(CONFIG_SOUTHBRIDGE_AMD_SB700)
 #include <southbridge/amd/sb700/sb700.h>
 #endif